"OpenTimestamps - Bitcoin-based timestamping protocol" matching MCP connectors:

Browser-based VR public speaking training with AI feedback. No headset required. Six MCP tools: list pricing plans, 3D practice environments, audience use cases, competitor comparison, FAQs, and quick-start guide.

Sudoku MCP server for free Sudoku puzzles, printable Sudoku worksheets, answer sheets and Sudoku Online playable collections. Eight tools generate verified unique puzzles, check uniqueness, analyze singles-based difficulty, validate progress and provide hints. Make packs of up to 20 puzzles in A4 or US Letter PDFs. Streamable HTTP; free API key and attribution required. Website: https://sudokumax.com — Setup: https://sudokumax.com/developers/mcp

Your AI agent builds interactive block-based courses over MCP; take them at learnwithagents.app.