diff --git a/docs/reference.md b/docs/reference.md
index 9ebf8c2..0cfabf5 100644
--- a/docs/reference.md
+++ b/docs/reference.md
@@ -31,4 +31,4 @@ Configuration is read from the following (in precedence order)
 | default.locale         | --locale          | en, en-us, en-gb, en-ca, en-au   | English dialect to correct to. |
 | default.extend-identifiers | \-            | table of strings | Corrections for identifiers. When the correction is blank, the word is never valid. When the correction is the key, the word is always valid. |
 | default.extend-words       | \-            | table of strings | Corrections for identifiers. When the correction is blank, the word is never valid. When the correction is the key, the word is always valid. |
-| type.<name>.binary         | <varied>      | <varied>   | See `default.` for child keys. |
+| type.<name>.binary         | <varied>      | <varied>   | See `default.` for child keys.  Run with `--type-list` to see available `<name>`s |
diff --git a/src/args.rs b/src/args.rs
index 1dd4863..dcec8dc 100644
--- a/src/args.rs
+++ b/src/args.rs
@@ -79,6 +79,10 @@ pub(crate) struct Args {
     /// Write the current configuration to file with `-` for stdout
     pub(crate) dump_config: Option<std::path::PathBuf>,
 
+    #[structopt(long, group = "mode")]
+    /// Show all supported file types.
+    pub(crate) type_list: bool,
+
     #[structopt(
         long,
         possible_values(&Format::variants()),
diff --git a/src/main.rs b/src/main.rs
index 4b9c00b..0d9139d 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -35,6 +35,8 @@ fn run() -> proc_exit::ExitResult {
 
     if let Some(output_path) = args.dump_config.as_ref() {
         run_dump_config(&args, output_path)
+    } else if args.type_list {
+        run_type_list(&args)
     } else {
         run_checks(&args)
     }
@@ -85,6 +87,54 @@ fn run_dump_config(args: &args::Args, output_path: &std::path::Path) -> proc_exi
     Ok(())
 }
 
+fn run_type_list(args: &args::Args) -> proc_exit::ExitResult {
+    let global_cwd = std::env::current_dir()?;
+
+    let path = &args.path[0];
+    let path = if path == std::path::Path::new("-") {
+        path.to_owned()
+    } else {
+        path.canonicalize().with_code(proc_exit::Code::USAGE_ERR)?
+    };
+    let cwd = if path == std::path::Path::new("-") {
+        global_cwd.as_path()
+    } else if path.is_file() {
+        path.parent().unwrap()
+    } else {
+        path.as_path()
+    };
+
+    let storage = typos_cli::policy::ConfigStorage::new();
+    let mut engine = typos_cli::policy::ConfigEngine::new(&storage);
+    engine.set_isolated(args.isolated);
+
+    let mut overrides = config::Config::default();
+    if let Some(path) = args.custom_config.as_ref() {
+        let custom = config::Config::from_file(path).with_code(proc_exit::Code::CONFIG_ERR)?;
+        overrides.update(&custom);
+    }
+    overrides.update(&args.config.to_config());
+    engine.set_overrides(overrides);
+
+    engine
+        .init_dir(cwd)
+        .with_code(proc_exit::Code::CONFIG_ERR)?;
+    let definitions = engine.file_types(cwd);
+
+    let stdout = std::io::stdout();
+    let mut handle = stdout.lock();
+    for def in definitions {
+        writeln!(
+            handle,
+            "{}: {}",
+            def.name(),
+            itertools::join(def.globs(), ", ")
+        )?;
+    }
+
+    Ok(())
+}
+
 fn run_checks(args: &args::Args) -> proc_exit::ExitResult {
     let global_cwd = std::env::current_dir()?;
 
diff --git a/src/policy.rs b/src/policy.rs
index cbb474d..bb0d896 100644
--- a/src/policy.rs
+++ b/src/policy.rs
@@ -67,7 +67,7 @@ impl<'s> ConfigEngine<'s> {
         self
     }
 
-    pub fn walk(&mut self, cwd: &std::path::Path) -> &crate::config::Walk {
+    pub fn walk(&self, cwd: &std::path::Path) -> &crate::config::Walk {
         let dir = self
             .configs
             .get(cwd)
@@ -75,6 +75,14 @@ impl<'s> ConfigEngine<'s> {
         self.get_walk(dir)
     }
 
+    pub fn file_types(&self, cwd: &std::path::Path) -> &[ignore::types::FileTypeDef] {
+        let dir = self
+            .configs
+            .get(cwd)
+            .expect("`init_dir` must be called first");
+        dir.type_matcher.definitions()
+    }
+
     pub fn policy(&self, path: &std::path::Path) -> Policy<'_, '_> {
         let dir = self.get_dir(path).expect("`walk()` should be called first");
         let file_config = dir.get_file_config(path);