Spotlight!

Keypirinha is a fast launcher for keyboard ninjas on Windows.

Quicksilver is a fast and free Mac OS X productivity application that gives you the power to control your Mac quickly and elegantly. Quicksilver learns your habits, making your everyday chores simple and efficient.

RecentX gives you fastest access to your files, folders, programs, websites and also clipboard history in Windows. What's special is that it automatically remembers your recent and favorite items so that you can access them faster than searching all the files, folders etc. You can assign tags to all of them. You will be surprised to see how much hassle it saves and makes computing really enjoyable. We have stuffed this app with innovations that will boost your productivity.

Cerebro is an open source and free electron-based productivity software alternative to Alfred and Spotlight. It is focused on speed and good UI and UX. In most cases you don't even need to open another application, because you can see results right in Cerebro, like google maps, IMDV movies or contact details.

Zazu is a new open source productivity app, that allows developers to be in the drivers seat. Unlike other solutions, there is no built-in integrations, so every plugin has the full scope of what Zazu has to offer.

Instantly find files, e-mails, and attachments stored anywhere on your PC with the free Copernic Desktop Search Home.

If you can see it, you can search it and share it from any device.Everything seen is remembered devices across all of your devices. Atlas pulls together all the threads of your digital life .Atlas Recall works with all the apps, websites, and services you love. No account authorizations required.Your digital life is more than just files. It’s the web pages, apps, emails, texts, chats, videos and more you use everyday. If you’ve seen it, you can search it with Atlas Recall

Hain is an ALT + SPACE launcher for Windows that looks and works similar to Alfred.

Scherlokk is a lightning fast file search utility build for precise and reliable search of every file which meets the search criteria. Music, pictures, bookmarks, documents, etc can be found quickly and easily. Search can be made on any kind of build in volume, portable volume (pendrives, memory cards, USB drives), network drive (AFP, SMB, FTP), Thunderbolt or Firewire device (CD/DVD, external HDD, slave computer), etc.

HoudahSpot is an advanced file search tool for Mac.