Pally is using X-Perl Unitframes (so i can see what my minions are targeting and what they are casting without having to look at their screens or have them targeted)
Trinity Bars 2.0 (toolbars)
Tankadin is the name of the mob, its not all that great but its fun sometimes, tells you how many deaths your ardent deffender tallent avoided the last fight (or total since u reset it last depending on how u set it up) and how much damage you mitigated with the talent. also reminds u to activate Righteous Fury
The xp bar (in the top left) is part of Trinity, you can cycle through Reputation or XP with it, and have it show % of lvl, Bubbles, how much rest remaining, or just X amount of exp like 478,548/614,400 - 15 (bubbles)

Priest, the blue bar under his portrait is the same XP bar from trinity bars 2.0
the 100% is part of CT Mod, i think its CT Unitframes, set to say either number of defecit or %. its also the numbers and %'s on the target (mixed with Mobinfo2)
The round buttons under the mini-map are all the mod buttons, that give u access to the options for each mod, like Trinity, CT Mod, CTRA, AtlasLoot Enhanced, Deadly Boss Mods, and X-Perl, etc etc.