Just go through and find the ones that fit your needs. I enjoy the one that opens the VSH menu right on screen in the XMB, and the one that lets you edit GAME.TXT, POPS.TXT, and VSH.TXT all from the XMB. I also enjoy the one that lets me save anywhere, as I do a solid amount of downloading on my PSP, and this allows me to organize on the fly.
I also got a homebrew that is the Netfront Beta Browser 4. It is the browser minus the memory limit, but it lacks the QWERTY keyboard set up and leaves you to the annoying phone keyboard. Needless to say, I only try to use this when sites won't load on the basic browser, as it doesn't seem to support the use of the save anywhere plugin due to it acting like a game when booting.
Really though, just find what you need. You might only want one or two plugins, you may want 15 or 20.