dnGREP - dnGrep allows you to search across files with easy-to-read results.
X1 Search - X1's Lightning-Fast Search Software. Premium Alternative to Windows Desktop and Outlook Search.
TextCrawler - Find and replace across multiple files
Everything by Voidtools - Everything. Locate files and folders by name instantly. Everything. Small installation file. Clean and simple user interface.
FileSeek - FileSeek is an easy-to-use file search app that includes advanced functionality for power users!
Agent Ransack - Agent Ransack is a tool for finding files and information on your hard drive fast and efficiently.