add placeholder content for other common markdown elements

Author: aifrim

docs/placeholder.mdx

@@ -2,11 +2,11 @@
 toc_min_heading_level: 2
 toc_max_heading_level: 6
 ---
-import Tabs from '@theme/Tabs';
-import TabItem from '@theme/TabItem';
-import TOCInline from '@theme/TOCInline';
 import BrowserWindow from '@site/src/components/BrowserWindow';
 import IframeWindow from '@site/src/components/BrowserWindow/IframeWindow';
+import TabItem from '@theme/TabItem';
+import Tabs from '@theme/Tabs';
+import TOCInline from '@theme/TOCInline';
 
 # Placeholder
 
@@ -172,7 +172,42 @@ This content is hidden by default.
 | Multiline   | Text        | And more      |
 | With breaks | Text        | And more      |
 
-### Browser
+## Blockquote
+
+> This is a blockquote.
+>
+> It can span multiple lines.
+
+> This is a blockquote with **Markdown** syntax.
+>
+> > It also has nested blockquotes.
+> > > Like this one.
+
+## Separator
+
+---
+
+## Lists
+
+1. First ordered item
+2. Second item
+    - Unordered sub-list. Lorem ipsum dolor sit amet, consectetur adipiscing elit.
+    - Another sub-list item
+3. Third item
+    1. Ordered sub-list
+    2. Another item
+
+## Links
+
+You can create [external links](https://docusaurus.io/docs/markdown-features#links) to other pages or websites.
+
+You can also create [internal links](./introduction.md) to other pages within the same site.
+
+## Styling
+
+You can use **bold**, *italic*, and `inline code` styles.
+
+## Browser
 
 ### Browser Window