1. Krugle is the complete enterprise solution for search targeted to the development organization. 

  2. OpenGrok is a fast and usable source code search and cross reference engine.

  3. Sourcegraph is a free, self-hosted code search and intelligence server that helps developers find, review, understand, and debug code. Use it with any Git code host for teams from 1 to 10,000+.

  4. The code snippet organizer for professional developers.