Doomlike Dungeons adds dungeons for those who want adventure, danger, and, uh, violence. This was inspired by Oblige, the level generator for Doom and similar games
survival dungeons worldgen
Creeper Queen Revived by Hawktalon
This mod adds the Creeper Queen, a giant creeper boss who spawns in creepers to defend herself.
JABBA by ProfMobius
Jabba (Just Another Better Barrel Attempt) is a storage mod aiming at making a better barrel than what is already out there. It introduces one block (the barrel itself), a set of upgrades and a dolly to move things around.
Styled Blocks by The_Wabbit
Adds missing stairs and slabs for standard Minecraft stone blocks. Add dozens of new block styles for standard block materials! Adds glass half-slabs.