diff --git a/packages/docusaurus-module-type-aliases/src/index.d.ts b/packages/docusaurus-module-type-aliases/src/index.d.ts
index 9714e56873..d61de8b4da 100644
--- a/packages/docusaurus-module-type-aliases/src/index.d.ts
+++ b/packages/docusaurus-module-type-aliases/src/index.d.ts
@@ -69,11 +69,41 @@ declare module '@generated/codeTranslations' {
   export default codeTranslations;
 }
 
-declare module '@theme/*';
-
 declare module '@theme-original/*';
 
-declare module '@docusaurus/*';
+declare module '@theme/Layout' {
+  import type {ReactNode} from 'react';
+
+  export interface Props {
+    readonly children: ReactNode;
+    readonly title?: string;
+    readonly description?: string;
+  }
+  export default function Layout(props: Props): JSX.Element;
+}
+
+declare module '@theme/Loading' {
+  import type {LoadingComponentProps} from 'react-loadable';
+
+  export default function Loading(props: LoadingComponentProps): JSX.Element;
+}
+
+declare module '@theme/NotFound' {
+  export default function NotFound(props: any): JSX.Element;
+}
+
+declare module '@theme/Root' {
+  import type {ReactNode} from 'react';
+
+  export interface Props {
+    readonly children: ReactNode;
+  }
+  export default function Root({children}: Props): JSX.Element;
+}
+
+declare module '@docusaurus/constants' {
+  export const DEFAULT_PLUGIN_ID: 'default';
+}
 
 declare module '@docusaurus/Head' {
   import type {HelmetProps} from 'react-helmet';
diff --git a/packages/docusaurus-plugin-ideal-image/.npmignore b/packages/docusaurus-plugin-ideal-image/.npmignore
index 4978437c5d..c59f11ebb5 100644
--- a/packages/docusaurus-plugin-ideal-image/.npmignore
+++ b/packages/docusaurus-plugin-ideal-image/.npmignore
@@ -1,2 +1 @@
-src
-copyUntypedFiles.js
\ No newline at end of file
+copyUntypedFiles.js
diff --git a/packages/docusaurus-plugin-ideal-image/package.json b/packages/docusaurus-plugin-ideal-image/package.json
index d682f2f4b6..37e3dbba8f 100644
--- a/packages/docusaurus-plugin-ideal-image/package.json
+++ b/packages/docusaurus-plugin-ideal-image/package.json
@@ -3,6 +3,7 @@
   "version": "2.0.0-beta.7",
   "description": "Docusaurus Plugin to generate an almost ideal image (responsive, lazy-loading, and low quality placeholder).",
   "main": "lib/index.js",
+  "types": "src/plugin-ideal-image.d.ts",
   "scripts": {
     "build": "tsc && node copyUntypedFiles.js",
     "watch": "node copyUntypedFiles.js && tsc --watch"
diff --git a/packages/docusaurus-plugin-ideal-image/src/index.ts b/packages/docusaurus-plugin-ideal-image/src/index.ts
index 70d3a6631e..d62ddcb9e8 100644
--- a/packages/docusaurus-plugin-ideal-image/src/index.ts
+++ b/packages/docusaurus-plugin-ideal-image/src/index.ts
@@ -5,7 +5,7 @@
  * LICENSE file in the root directory of this source tree.
  */
 import {LoadContext, Plugin} from '@docusaurus/types';
-import {PluginOptions} from './types';
+import type {PluginOptions} from '@docusaurus/plugin-ideal-image';
 import {Configuration} from 'webpack';
 
 import path from 'path';
diff --git a/packages/docusaurus-plugin-ideal-image/src/plugin-ideal-image.d.ts b/packages/docusaurus-plugin-ideal-image/src/plugin-ideal-image.d.ts
new file mode 100644
index 0000000000..6e2a3eff21
--- /dev/null
+++ b/packages/docusaurus-plugin-ideal-image/src/plugin-ideal-image.d.ts
@@ -0,0 +1,50 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ */
+
+declare module '@docusaurus/plugin-ideal-image' {
+  export type PluginOptions = {
+    /**
+     * Filename template for output files.
+     */
+    name?: string;
+    /**
+     * Specify all widths you want to use; if a specified size exceeds the original image's width, the latter will be used (i.e. images won't be scaled up). You may also declare a default sizes array in the loader options in your webpack.config.js.
+     */
+    sizes?: number[];
+    /**
+     * Specify one width you want to use; if the specified size exceeds the original image's width, the latter will be used (i.e. images won't be scaled up)
+     */
+    size?: number;
+    /**
+     * As an alternative to manually specifying sizes, you can specify min, max and steps, and the sizes will be generated for you.
+     */
+    min?: number;
+    /**
+     * See min above
+     */
+    max?: number;
+    /**
+     * Configure the number of images generated between min and max (inclusive)
+     */
+    steps?: number;
+    /**
+     * JPEG compression quality
+     */
+    quality?: number;
+  };
+}
+
+declare module '@theme/IdealImage' {
+  import type {ComponentProps} from 'react';
+
+  export interface Props extends ComponentProps<'img'> {
+    img: any;
+  }
+  export default function IdealImage(props: Props): JSX.Element;
+}
+
+declare module '@endiliey/react-ideal-image';
diff --git a/packages/docusaurus-plugin-ideal-image/src/types.ts b/packages/docusaurus-plugin-ideal-image/src/types.ts
deleted file mode 100644
index 2f034e2129..0000000000
--- a/packages/docusaurus-plugin-ideal-image/src/types.ts
+++ /dev/null
@@ -1,37 +0,0 @@
-/**
- * Copyright (c) Facebook, Inc. and its affiliates.
- *
- * This source code is licensed under the MIT license found in the
- * LICENSE file in the root directory of this source tree.
- */
-
-export interface PluginOptions {
-  /**
-   * Filename template for output files.
-   */
-  name?: string;
-  /**
-   * Specify all widths you want to use; if a specified size exceeds the original image's width, the latter will be used (i.e. images won't be scaled up). You may also declare a default sizes array in the loader options in your webpack.config.js.
-   */
-  sizes?: number[];
-  /**
-   * Specify one width you want to use; if the specified size exceeds the original image's width, the latter will be used (i.e. images won't be scaled up)
-   */
-  size?: number;
-  /**
-   * As an alternative to manually specifying sizes, you can specify min, max and steps, and the sizes will be generated for you.
-   */
-  min?: number;
-  /**
-   * See min above
-   */
-  max?: number;
-  /**
-   * Configure the number of images generated between min and max (inclusive)
-   */
-  steps?: number;
-  /**
-   * JPEG compression quality
-   */
-  quality?: number;
-}
diff --git a/packages/docusaurus-theme-classic/src/types.d.ts b/packages/docusaurus-theme-classic/src/types.d.ts
index d2c8d415c8..cabd03ed3e 100644
--- a/packages/docusaurus-theme-classic/src/types.d.ts
+++ b/packages/docusaurus-theme-classic/src/types.d.ts
@@ -19,6 +19,10 @@ declare module '@theme/AnnouncementBar' {
   export default AnnouncementBar;
 }
 
+declare module '@theme/BackToTopButton' {
+  export default function BackToTopButton(): JSX.Element;
+}
+
 declare module '@theme/BlogListPaginator' {
   import type {Metadata} from '@theme/BlogListPage';
 
@@ -505,6 +509,10 @@ declare module '@theme/NavbarItem' {
   export default NavbarItem;
 }
 
+declare module '@theme/SearchBar' {
+  export default function SearchBar(): JSX.Element;
+}
+
 declare module '@theme/TabItem' {
   import type {ReactNode} from 'react';
 
diff --git a/packages/docusaurus/src/client/exports/constants.ts b/packages/docusaurus/src/client/exports/constants.ts
index 48fa05bd69..e7e5a1dcc2 100644
--- a/packages/docusaurus/src/client/exports/constants.ts
+++ b/packages/docusaurus/src/client/exports/constants.ts
@@ -5,16 +5,5 @@
  * LICENSE file in the root directory of this source tree.
  */
 
-/*
-// eslint-disable-next-line no-restricted-imports
-export {
-  // constants were only available on node
-  // this makes some useful constants available to frontend/themes too
-  // import {DEFAULT_PLUGIN_ID} '@docusaurus/constants'
-  DEFAULT_PLUGIN_ID,
-} from '../../constants';
- */
-
-// Not duplicating the constants seems to produce
-// weird TS compilation side-effects
+// Constants used on the client-side: duplicated from server-side code
 export const DEFAULT_PLUGIN_ID = 'default';
diff --git a/packages/docusaurus/src/client/exports/useGlobalData.ts b/packages/docusaurus/src/client/exports/useGlobalData.ts
index 15c9034acc..155ee22e6f 100644
--- a/packages/docusaurus/src/client/exports/useGlobalData.ts
+++ b/packages/docusaurus/src/client/exports/useGlobalData.ts
@@ -6,12 +6,7 @@
  */
 
 import useDocusaurusContext from './useDocusaurusContext';
-
-// TODO annoying constant duplication
-// if we import something from outside the /client folder,
-// the tsc directory structure is affected
-// import {DEFAULT_PLUGIN_ID} from '../../constants';
-const DEFAULT_PLUGIN_ID = 'default';
+import {DEFAULT_PLUGIN_ID} from './constants';
 
 export default function useGlobalData(): Record<string, unknown> {
   const {globalData} = useDocusaurusContext();
diff --git a/website/src/types.d.ts b/website/src/types.d.ts
new file mode 100644
index 0000000000..75278b9bdd
--- /dev/null
+++ b/website/src/types.d.ts
@@ -0,0 +1 @@
+/// <reference types="@docusaurus/plugin-ideal-image" />