diff --git a/README.md b/README.md
index 947749c..5e32d0e 100644
--- a/README.md
+++ b/README.md
@@ -52,11 +52,11 @@ To configure via `use-package`, adapt the following example as desired:
 
 ### Customization
 
-| Variable                       | Type             | Default                                                                                       | Description                                   |
-|:-----------------------------|:-----------------|:----------------------------------------------------------------------------------------------|:----------------------------------------------|
-| `snap-indent-excluded-modes` | symbol list      | `'(elm-mode haskell-mode makefile-gmake-mode makefile-mode occam-mode python-mode yaml-mode)` | Major modes in which to ignore activation     |
-| `snap-indent-format`         | function or list | `nil`                                                                                         | Additional formatting to apply when indenting |
-| `snap-indent-on-save`        | boolean          | `nil`                                                                                         | Whether to indent the entire buffer on save   |
+| Variable                     | Type             | Default                                                                                                                                                                                                                                                                | Description                                   |
+| :--------------------------- | :--------------- | :--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | :-------------------------------------------- |
+| `snap-indent-excluded-modes` | symbol list      | `(cmake-ts-mode coffee-mode conf-mode elm-mode haml-mode haskell-mode makefile-automake-mode makefile-bsdmake-mode makefile-gmake-mode makefile-imake-mode makefile-makepp-mode makefile-mode occam-mode python-mode python-ts-mode slim-mode yaml-mode yaml-ts-mode)` | Major modes in which to ignore activation     |
+| `snap-indent-format`         | function or list | `nil`                                                                                                                                                                                                                                                                  | Additional formatting to apply when indenting |
+| `snap-indent-on-save`        | boolean          | `nil`                                                                                                                                                                                                                                                                  | Whether to indent the entire buffer on save   |
 
 ### Additional formatting
 
diff --git a/snap-indent.el b/snap-indent.el
index 3f00770..c516bec 100644
--- a/snap-indent.el
+++ b/snap-indent.el
@@ -49,13 +49,24 @@
   :prefix "snap-indent-"
   :group 'indent)
 
-(defcustom snap-indent-excluded-modes '(elm-mode
+(defcustom snap-indent-excluded-modes '(cmake-ts-mode
+                                        coffee-mode
+                                        conf-mode
+                                        elm-mode
+                                        haml-mode
                                         haskell-mode
+                                        makefile-automake-mode
+                                        makefile-bsdmake-mode
                                         makefile-gmake-mode
+                                        makefile-imake-mode
+                                        makefile-makepp-mode
                                         makefile-mode
                                         occam-mode
                                         python-mode
-                                        yaml-mode)
+                                        python-ts-mode
+                                        slim-mode
+                                        yaml-mode
+                                        yaml-ts-mode)
   "Modes in which `snap-indent-mode' should not be activated.
 This permits activation for `prog-mode' while excluding certain modes derived
 from `prog-mode', for example."