Not all Fullbright packs are created equal. Some are "vanilla only" (meaning no block textures change, just the light). Others combine Fullbright with PvP improvements. Here are the top five for 1.8.8:
: Since it is a resource pack and not a mod, you can still earn achievements in your worlds. fullbright texture pack 1.8.8
In the game menu, move "Fullbright" to the (the "Selected" column). Not all Fullbright packs are created equal