aiknow is a vertical search engine for AI tools. Instead of browsing a directory, type what you need in plain words, like "free AI coding agent for Windows" or "MCP server for databases". It understands the task plus filters (free, open source, has API, platform, country, model family), searches 3,600+ curated AI apps, models, APIs, agents, MCP servers and skills, and an AI pick tells you which result fits best. Free, no sign-up, English and Chinese.