I got a bunch...*ahem*
AutoPlugin ll (2): An easy way to install PS Vita/PSP plugins!
iTLS Enso: Using the Vita's web browser or going to play a custom online Vita game server?
You're going need this.
VitaGrafix and VitaGrafix Configurator: Select PS Vita games can be configured to your liking!
Want to increase a game's resolution and framerate or set the anti-aliasing level? It allows you to do so and you can get it from AutoPlugin ll!
vitaQuakelll (3): It's PC Quake 3 in your PS Vita along with OpenArena (kind of, it isn't running the actual OpenArena engine) and Quake 3 Team Arena!
Sure...it's not going to replace the PC version for some mods, its mouse's emulation is off, and...you wouldn't want to play this version online, but its recent update shows the Vita community at their best working on vitaGL among many others!
NetStream: The web browser on the Vita giving you problems with YouTube, isn't working, or is video playback too blurry for you?
This app should be a good alternative as you can watch Youtube videos, HTTP and FTP server videos, and videos from your local storage at up to 720p resolution!
You can even download videos or make them as audio files for offline use!
(Oh, and I should mention that you can even see comments on YouTube videos!)
Noboru: This app allows you to read manga and comics from various sites and allow you to download them for offline reading!
(Personally though, if you are an English speaker, I only found that the MangaTown and the ReadComicsOnline sites were working for me, but you may want to use the Vita's web browser or other devices for other sites)