Gnome-Pie!

Listary is an excellent enhancement utility for list controls used everywhere: Windows Explorer, Task Manager, Registry Editor, and innumerable third-party applications.It searches folders, files or anything else as-you-type. Autocomplete, masks, hotkeys, regular expressions (pro version only) are good time-saving features.

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.

GNOME Do allows you to quickly search for many items present on your desktop or the web, and perform useful actions on those items.

Kupfer is a command tool heavily inspired by Quicksilver ; you do not use it to search your files, you use it to summon an application or document quickly by typing the first parts of its name. Kupfer is written using Python and has a flexible architecture. Objects that it can access are implemented in plugins, and new plugins can be written quickly. The philosophy of Kupfer is simplicity. The implementation is simple, makes the easy things work first, and does not overdesign unnecessary parts of the program. When you run kupfer, it launches, then anytime you type Kupfers keybinding -- immediately its window is presented ready for a new query. »

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

The idea behind Circle Dock is that the dock should appear where your mouse is instead of you having to move your mouse to the dock like with other programs. This is accomplished by making the dock a circular or spiral shape so that it can be placed anywhere, even near the edge of the screen. The offscreen portions of the dock are easily reached by just scrolling with your mouse wheel or arrow keys.

dmenu is a dynamic menu for X, originally designed for dwm. It manages large numbers of user-defined menu items efficiently.

Mutate is a simple launcher inspired by Alfred for Ubuntu.Be more productive with hotkeys, keywords and file actions at your fingertips.

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.

Disklens, the Spotlight alternative, lets you quickly and easily find about anything on your Mac.

A handy tool to start application by keyboard.

Slingshot is the lightweight and stylish app launcher designed for elementary OS .

Launch Box is generally an application launcher. It's very influenced by Quicksilver for Mac OSX. Remember that this is only a first release so don't get your hopes up too much. Launch Box is written for the GNOME 2.10 platform and depends on GTK+ 2.6, evolution-data-server 1.2 and gnome-menus. These are currently hard dependencies but the plan is to split out the backends into different optional backends.