diff --git a/CHANGELOG.md b/CHANGELOG.md
index 89ea959..59d589b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,8 @@ The format is based on [Keep a Changelog].
 * Use `perltidy` as default formatter for `cperl-mode` ([#260]).
 * The `perltidy` formatter now supports Emacs indentation and line length
   settings ([#261]).
+* Indent level is now determined for `graphql-mode`, `html-mode`, `ruby-mode`,
+  `ruby-ts-mode`, `svelte-mode`, and `yaml-mode` ([#258]).
 
 ### Formatters
 * [`dprint`](https://dprint.dev) for various (depending on
@@ -31,6 +33,7 @@ The format is based on [Keep a Changelog].
 [#209]: https://github.com/radian-software/apheleia/pull/209
 [#229]: https://github.com/radian-software/apheleia/pull/229
 [#257]: https://github.com/radian-software/apheleia/pull/257
+[#258]: https://github.com/radian-software/apheleia/pull/258
 [#260]: https://github.com/radian-software/apheleia/pull/260
 [#261]: https://github.com/radian-software/apheleia/pull/261
 [#263]: https://github.com/radian-software/apheleia/pull/263
diff --git a/apheleia-utils.el b/apheleia-utils.el
index 07a358b..7e3820f 100644
--- a/apheleia-utils.el
+++ b/apheleia-utils.el
@@ -38,6 +38,8 @@ always returns nil to defer to the formatter."
               (cperl-mode 'cperl-indent-level)
               (css-mode 'css-indent-offset)
               (css-ts-mode 'css-indent-offset)
+              (graphql-mode 'graphql-indent-level)
+              (html-mode 'sgml-basic-offset)
               (js-jsx-mode 'js-indent-level)
               (js-ts-mode 'js-indent-level)
               (js-mode 'js-indent-level)
@@ -50,11 +52,15 @@ always returns nil to defer to the formatter."
               (robot-mode 'robot-mode-basic-offset)
               (perl-mode 'perl-indent-level)
               (python-mode 'python-indent-offset)
+              (ruby-mode 'ruby-indent-level)
+              (ruby-ts-mode 'ruby-indent-level)
               (scss-mode 'css-indent-offset)
+              (svelte-mode 'svelte-basic-offset)
               (web-mode 'web-mode-indent-style)
               (tsx-ts-mode 'typescript-ts-mode-indent-offset)
               (typescript-mode 'typescript-indent-level)
-              (typescript-ts-mode 'typescript-ts-mode-indent-offset))))
+              (typescript-ts-mode 'typescript-ts-mode-indent-offset)
+              (yaml-mode 'yaml-indent-offset))))
 
     (when-let ((indent (and indent-var
                             (boundp indent-var)