diff --git a/NAMESPACE b/NAMESPACE
index d03570d983..5a3038454a 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -737,6 +737,7 @@ export(theme_sub_axis_top)
 export(theme_sub_axis_x)
 export(theme_sub_axis_y)
 export(theme_sub_legend)
+export(theme_sub_palette)
 export(theme_sub_panel)
 export(theme_sub_plot)
 export(theme_sub_strip)
diff --git a/NEWS.md b/NEWS.md
index 6a9d993fe8..ff180b8f20 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -33,6 +33,10 @@
 * New `position_dodge2(group.row)` argument that can be set to `"many"` to
   dodge groups with more than one row, such as in `geom_violin()` 
   (@teunbrand, #6663)
+* `palette.{aes}.discrete` and `palette.{aes}.continuous` are now documented
+  in `theme()` and have a new helper `theme_sub_palette()`.
+  `strip.position.x` and `strip.position.y` are also documented and work
+  with `theme_sub_strip()` (@arcresu, #6829).
 
 # ggplot2 4.0.2
 
diff --git a/R/theme-sub.R b/R/theme-sub.R
index f7644fc08d..e3ee89ec1d 100644
--- a/R/theme-sub.R
+++ b/R/theme-sub.R
@@ -127,6 +127,18 @@ theme_sub_legend <- function(
   subtheme(find_args(), "legend.")
 }
 
+#' @export
+#' @describeIn subtheme Theme specification for palettes.
+theme_sub_palette <- function(..., colour.continuous, colour.discrete,
+                              fill.continuous, fill.discrete, alpha.continuous,
+                              alpha.discrete, linewidth.continuous,
+                              linewidth.discrete, size.continuous,
+                              size.discrete, shape.continuous, shape.discrete,
+                              linetype.continuous, linetype.discrete) {
+  warn_dots_empty()
+  subtheme(find_args(), "palette.")
+}
+
 #' @export
 #' @describeIn subtheme Theme specification for the panels.
 theme_sub_panel <- function(..., background, border,
@@ -149,7 +161,8 @@ theme_sub_plot <- function(..., background, title, title.position, subtitle, cap
 #' @export
 #' @describeIn subtheme Theme specification for facet strips.
 theme_sub_strip <- function(..., background, background.x, background.y, clip,
-                            placement, text, text.x, text.x.bottom, text.x.top,
+                            placement, placement.x, placement.y, text, text.x,
+                            text.x.bottom, text.x.top,
                             text.y, text.y.left, text.y.right,
                             switch.pad.grid, switch.pad.wrap) {
   warn_dots_empty()
@@ -160,7 +173,7 @@ subtheme_param_doc <- function() {
   funs <- list(
     theme_sub_axis, theme_sub_axis_x, theme_sub_axis_y, theme_sub_axis_bottom,
     theme_sub_axis_top, theme_sub_axis_left, theme_sub_axis_right, theme_sub_legend,
-    theme_sub_panel, theme_sub_plot, theme_sub_strip
+    theme_sub_panel, theme_sub_plot, theme_sub_strip, theme_sub_palette
   )
   args <- sort(unique(unlist(lapply(funs, fn_fmls_names), use.names = FALSE)))
   args <- setdiff(args, "...")
diff --git a/R/theme.R b/R/theme.R
index d263ff0fe6..7496fa9c35 100644
--- a/R/theme.R
+++ b/R/theme.R
@@ -132,6 +132,21 @@
 #' @param legend.box.spacing The spacing between the plotting area and the
 #'   legend box (`unit`); inherits from `spacing`.
 #'
+#' @param palette.colour.discrete,palette.colour.continuous,palette.fill.discrete,palette.fill.continuous
+#'   default palettes for the colour and fill aesthetics to use for discrete or
+#'   continuous data. Can be a character vector of colours or a palette function
+#'   such as [scales::pal_hue()]. `palette.fill.discrete` inherits from
+#'   palette.colour.discrete` and `palette.fill.continuous` inherits from
+#'   `palette.colour.continuous`.
+#' @param palette.alpha.discrete,palette.linewidth.discrete,palette.size.discrete,palette.shape.discrete,palette.linetype.discrete
+#'   default palette to use for discrete scales for the corresponding aesthetic.
+#'   See the `palette` parameter of [discrete_scale()] and
+#'   `vignette("ggplot2-specs")` for allowed values.
+#' @param palette.alpha.continuous,palette.linewidth.continuous,palette.size.continuous,palette.shape.continuous,palette.linetype.continuous
+#'   default palette to use for continuous scales for the corresponding aesthetic.
+#'   See the `palette` parameter of [continuous_scale()] and
+#'   `vignette("ggplot2-specs")` for allowed values.
+#'
 #' @param panel.background background of plotting area, drawn underneath plot
 #'   ([element_rect()]; inherits from `rect`)
 #' @param panel.border border around plotting area, drawn on top of plot so that
@@ -192,9 +207,11 @@
 #'   inherits from `rect`). Horizontal facet background (`strip.background.x`)
 #'   & vertical facet background (`strip.background.y`) inherit from
 #'   `strip.background` or can be specified separately
-#' @param strip.placement placement of strip with respect to axes,
-#'    either "inside" or "outside". Only important when axes and strips are
-#'    on the same side of the plot.
+#' @param strip.placement,strip.placement.x,strip.placement.y
+#'    placement of strip with respect to axes, either "inside" or "outside".
+#'    Only important when axes and strips are on the same side of the plot.
+#'    Horizontal (`strip.placement.x`) & vertical (`strip.placement.y`) placements
+#'    inherit from `strip.placement` or can be specified separately
 #' @param strip.clip should strip background edges and strip labels be clipped
 #'   to the extend of the strip background? Options are `"on"` to clip, `"off"`
 #'   to disable clipping or `"inherit"` (default) to take the clipping setting
@@ -444,6 +461,20 @@ theme <- function(...,
                   legend.box.margin,
                   legend.box.background,
                   legend.box.spacing,
+                  palette.colour.discrete,
+                  palette.colour.continuous,
+                  palette.fill.discrete,
+                  palette.fill.continuous,
+                  palette.alpha.discrete,
+                  palette.alpha.continuous,
+                  palette.linewidth.discrete,
+                  palette.linewidth.continuous,
+                  palette.size.discrete,
+                  palette.size.continuous,
+                  palette.shape.discrete,
+                  palette.shape.continuous,
+                  palette.linetype.discrete,
+                  palette.linetype.continuous,
                   panel.background,
                   panel.border,
                   panel.spacing,
@@ -474,6 +505,8 @@ theme <- function(...,
                   strip.background.y,
                   strip.clip,
                   strip.placement,
+                  strip.placement.x,
+                  strip.placement.y,
                   strip.text,
                   strip.text.x,
                   strip.text.x.bottom,
diff --git a/man/subtheme.Rd b/man/subtheme.Rd
index 1200580280..349316aeb2 100644
--- a/man/subtheme.Rd
+++ b/man/subtheme.Rd
@@ -10,6 +10,7 @@
 \alias{theme_sub_axis_left}
 \alias{theme_sub_axis_right}
 \alias{theme_sub_legend}
+\alias{theme_sub_palette}
 \alias{theme_sub_panel}
 \alias{theme_sub_plot}
 \alias{theme_sub_strip}
@@ -122,6 +123,24 @@ theme_sub_legend(
   box.spacing
 )
 
+theme_sub_palette(
+  ...,
+  colour.continuous,
+  colour.discrete,
+  fill.continuous,
+  fill.discrete,
+  alpha.continuous,
+  alpha.discrete,
+  linewidth.continuous,
+  linewidth.discrete,
+  size.continuous,
+  size.discrete,
+  shape.continuous,
+  shape.discrete,
+  linetype.continuous,
+  linetype.discrete
+)
+
 theme_sub_panel(
   ...,
   background,
@@ -162,6 +181,8 @@ theme_sub_strip(
   background.y,
   clip,
   placement,
+  placement.x,
+  placement.y,
   text,
   text.x,
   text.x.bottom,
@@ -176,7 +197,7 @@ theme_sub_strip(
 \arguments{
 \item{...}{Not in use, expected to be empty.}
 
-\item{axis.line, background, background.x, background.y, border, box, box.background, box.just, box.margin, box.spacing, byrow, caption, caption.position, clip, direction, frame, grid, grid.major, grid.major.x, grid.major.y, grid.minor, grid.minor.x, grid.minor.y, heights, justification, justification.bottom, justification.inside, justification.left, justification.right, justification.top, key, key.height, key.justification, key.size, key.spacing, key.spacing.x, key.spacing.y, key.width, line, location, margin, minor.ticks, minor.ticks.length, ontop, placement, position, position.inside, spacing, spacing.x, spacing.y, subtitle, switch.pad.grid, switch.pad.wrap, tag, tag.location, tag.position, text, text.position, text.x, text.x.bottom, text.x.top, text.y, text.y.left, text.y.right, ticks, ticks.length, title, title.position, widths}{Arguments that are renamed and passed on to \code{\link[=theme]{theme()}}.}
+\item{alpha.continuous, alpha.discrete, axis.line, background, background.x, background.y, border, box, box.background, box.just, box.margin, box.spacing, byrow, caption, caption.position, clip, colour.continuous, colour.discrete, direction, fill.continuous, fill.discrete, frame, grid, grid.major, grid.major.x, grid.major.y, grid.minor, grid.minor.x, grid.minor.y, heights, justification, justification.bottom, justification.inside, justification.left, justification.right, justification.top, key, key.height, key.justification, key.size, key.spacing, key.spacing.x, key.spacing.y, key.width, line, linetype.continuous, linetype.discrete, linewidth.continuous, linewidth.discrete, location, margin, minor.ticks, minor.ticks.length, ontop, placement, placement.x, placement.y, position, position.inside, shape.continuous, shape.discrete, size.continuous, size.discrete, spacing, spacing.x, spacing.y, subtitle, switch.pad.grid, switch.pad.wrap, tag, tag.location, tag.position, text, text.position, text.x, text.x.bottom, text.x.top, text.y, text.y.left, text.y.right, ticks, ticks.length, title, title.position, widths}{Arguments that are renamed and passed on to \code{\link[=theme]{theme()}}.}
 }
 \value{
 A \code{theme}-class object that can be added to a plot.
@@ -204,6 +225,8 @@ keeping theme declarations more organised.
 
 \item \code{theme_sub_legend()}: Theme specification for the legend.
 
+\item \code{theme_sub_palette()}: Theme specification for palettes.
+
 \item \code{theme_sub_panel()}: Theme specification for the panels.
 
 \item \code{theme_sub_plot()}: Theme specification for the whole plot.
diff --git a/man/theme.Rd b/man/theme.Rd
index 66a9be0d32..4b7f3a4928 100644
--- a/man/theme.Rd
+++ b/man/theme.Rd
@@ -111,6 +111,20 @@ theme(
   legend.box.margin,
   legend.box.background,
   legend.box.spacing,
+  palette.colour.discrete,
+  palette.colour.continuous,
+  palette.fill.discrete,
+  palette.fill.continuous,
+  palette.alpha.discrete,
+  palette.alpha.continuous,
+  palette.linewidth.discrete,
+  palette.linewidth.continuous,
+  palette.size.discrete,
+  palette.size.continuous,
+  palette.shape.discrete,
+  palette.shape.continuous,
+  palette.linetype.discrete,
+  palette.linetype.continuous,
   panel.background,
   panel.border,
   panel.spacing,
@@ -141,6 +155,8 @@ theme(
   strip.background.y,
   strip.clip,
   strip.placement,
+  strip.placement.x,
+  strip.placement.y,
   strip.text,
   strip.text.x,
   strip.text.x.bottom,
@@ -301,6 +317,19 @@ inherits from \code{rect})}
 \item{legend.box.spacing}{The spacing between the plotting area and the
 legend box (\code{unit}); inherits from \code{spacing}.}
 
+\item{palette.colour.discrete, palette.colour.continuous, palette.fill.discrete, palette.fill.continuous}{default palettes for the colour and fill aesthetics to use for discrete or
+continuous data. Can be a character vector of colours or a palette function
+such as \code{\link[scales:pal_hue]{scales::pal_hue()}}. \code{palette.fill.discrete} inherits from
+palette.colour.discrete\code{and}palette.fill.continuous\verb{inherits from}palette.colour.continuous`.}
+
+\item{palette.alpha.discrete, palette.linewidth.discrete, palette.size.discrete, palette.shape.discrete, palette.linetype.discrete}{default palette to use for discrete scales for the corresponding aesthetic.
+See the \code{palette} parameter of \code{\link[=discrete_scale]{discrete_scale()}} and
+\code{vignette("ggplot2-specs")} for allowed values.}
+
+\item{palette.alpha.continuous, palette.linewidth.continuous, palette.size.continuous, palette.shape.continuous, palette.linetype.continuous}{default palette to use for continuous scales for the corresponding aesthetic.
+See the \code{palette} parameter of \code{\link[=continuous_scale]{continuous_scale()}} and
+\code{vignette("ggplot2-specs")} for allowed values.}
+
 \item{panel.background}{background of plotting area, drawn underneath plot
 (\code{\link[=element_rect]{element_rect()}}; inherits from \code{rect})}
 
@@ -378,9 +407,10 @@ to the extend of the strip background? Options are \code{"on"} to clip, \code{"o
 to disable clipping or \code{"inherit"} (default) to take the clipping setting
 from the parent viewport.}
 
-\item{strip.placement}{placement of strip with respect to axes,
-either "inside" or "outside". Only important when axes and strips are
-on the same side of the plot.}
+\item{strip.placement, strip.placement.x, strip.placement.y}{placement of strip with respect to axes, either "inside" or "outside".
+Only important when axes and strips are on the same side of the plot.
+Horizontal (\code{strip.placement.x}) & vertical (\code{strip.placement.y}) placements
+inherit from \code{strip.placement} or can be specified separately}
 
 \item{strip.text, strip.text.x, strip.text.y, strip.text.x.top, strip.text.x.bottom, strip.text.y.left, strip.text.y.right}{facet labels (\code{\link[=element_text]{element_text()}}; inherits from  \code{text}). Horizontal facet labels (\code{strip.text.x}) & vertical
 facet labels (\code{strip.text.y}) inherit from \code{strip.text} or can be specified
diff --git a/tests/testthat/test-theme-sub.R b/tests/testthat/test-theme-sub.R
index 32d4f98d92..7a1247e05c 100644
--- a/tests/testthat/test-theme-sub.R
+++ b/tests/testthat/test-theme-sub.R
@@ -13,6 +13,8 @@ test_that("subtheme functions rename arguments as intended", {
   expect_equal(theme_sub_axis_left(ticks = line),   theme(axis.ticks.y.left = line))
   expect_equal(theme_sub_axis_right(ticks = line),  theme(axis.ticks.y.right = line))
   expect_equal(theme_sub_legend(key = rect),        theme(legend.key = rect))
+  expect_equal(theme_sub_palette(fill.discrete = c()),
+                                                    theme(palette.fill.discrete = c()))
   expect_equal(theme_sub_panel(border = rect),      theme(panel.border = rect))
   expect_equal(theme_sub_plot(background = rect),   theme(plot.background = rect))
   expect_equal(theme_sub_strip(background = rect),  theme(strip.background = rect))
@@ -41,6 +43,7 @@ test_that("theme elements are covered in `theme_sub_*()` functions", {
   fmls <- c(fmls, paste0("axis.",   fn_fmls_names(theme_sub_axis_right), ".y.right"))
   fmls <- c(fmls, paste0("legend.", fn_fmls_names(theme_sub_legend)))
   fmls <- c(fmls, paste0("plot.",   fn_fmls_names(theme_sub_plot)))
+  fmls <- c(fmls, paste0("palette.",fn_fmls_names(theme_sub_palette)))
   fmls <- c(fmls, paste0("panel.",  fn_fmls_names(theme_sub_panel)))
   fmls <- c(fmls, paste0("strip.",  fn_fmls_names(theme_sub_strip)))
 
diff --git a/tests/testthat/test-theme.R b/tests/testthat/test-theme.R
index 55f9b8d47d..42c77b35f8 100644
--- a/tests/testthat/test-theme.R
+++ b/tests/testthat/test-theme.R
@@ -693,3 +693,14 @@ test_that("legends are placed correctly when using stretchy spacing", {
     p + theme(legend.position = "top", legend.spacing.x = unit(1, "null"))
   )
 })
+
+test_that("all theme elements are documented", {
+  all_elems <- names(.element_tree)
+  doc_fmls <- fn_fmls_names(theme)
+  missing_elems <- setdiff(all_elems, doc_fmls)
+
+  expect(length(missing_elems) == 0, c(
+    "Expected all elements in `.element_tree` to have corresponding parameters in `theme()`.",
+    sprintf("Element is missing from theme(): %s", paste(missing_elems))
+  ))
+})