The Claude Code ecosystem you did not know existed 18 repositories, sorted by what they do: Official Anthropic (173k stars) - the official skill library. PDF, DOCX, XLSX, PPTX manipulation and art generation, straight from the source. (24k stars) - plugins aimed at knowledge workers rather than engineers, for Claude Cowork and Claude Code. (6k stars) - a GitHub Action that reviews every diff for vulnerabilities. (8k stars) - the official Python SDK for building on top of Claude Code. Agent Harness (280k stars) - a 7-phase workflow from brainstorm to review. It deletes implementation written before a failing test exists. In Anthropic's official marketplace since January. (245k stars) - 68 subagents, 286 skills, 94 commands, MIT. Built by an Anthropic hackathon winner. (130k stars) - Garry Tan's own setup, with opinionated agent roles for product, design, engineering, release and QA. (70k stars) - orchestration platform for running many agents against one codebase. Skills (46k stars) - 50 marketing skills. One writes down who your customer is, the other 49 read that file first. (16k stars) - grades anything Claude writes out of 50 across five dimensions and rewrites below 35. (123k stars) - 79 design styles, 192 palettes, and a list of what to avoid per industry. (18k stars) - 15 skills for keeping the context window small. Loads only what the task needs. (4.5k stars) - from the Remotion team. Describe a video, get React code that renders it. MCP (93k stars) - the catalogue everyone starts from when wiring Claude to something external. (6k stars) - 78 tools that put Claude Code inside your TradingView chart. It writes Pine Script and fixes its own compile errors. (2.5k stars) - brings MCP tools into ChatGPT, Grok, Perplexity and Gemini. Lists (53k stars) - the hand-curated list. Contributions get reviewed, bulk AI submissions get rejected. (1.3k stars) - the opposite approach. An automated index that has 1061 plugin repositories catalogued as of August 31.