Actually, the first UF is kind of blurry, so it's hard to tell which it is. If it is ag_UF, it's a custom layout. If it's PitBull, it's an old screenshot because PitBull no longer runs the xp bar under the portrait. (X-Perl is the UF mod in the second screenshot, as already mentioned.)
The xp bar is called FuBar_FuXPFu - it requires FuBar (that bar along the top with the plugins in it) to attach itself to. It can also show reputation, and the colors are configurable for it. The latest versions of this, FuBar, and PitBull can be found at
http://files.wowace.com
The buff mod is CT_BuffMod as someone previously mentioned. It is part of the CT package, which can be downloaded here:
http://www.ctmod.net/ ElkBuffBars is what I use to get that style of buffs and can be downloaded from wowace as well. It will plug into your FuBar and is more configurable than CT_BuffMod.
For discord textures, go to
www.wowtextures.com - most of those should already be in a format to use in-game. If you want to create your own, there's a tutorial on that site as well.