Scherlokk - Mac OS X application. Simple and user friendly, Scherlokk will find your media and missed files - quickly.
DocFetcher - DocFetcher is a portable German/English open source desktop search application.
Slingscold - Slingscold is a lightweight application launcher similar to Launchpad in Mac OS X.
Everything by Voidtools - Everything. Locate files and folders by name instantly. Everything. Small installation file. Clean and simple user interface.
kupfer - Kupfer is a command tool heavily inspired by https://alternativeto.
Agent Ransack - Agent Ransack is a tool for finding files and information on your hard drive fast and efficiently.