A variety of unimplemented mobs from Minecraft's past Mob Votes remain unintegrated into the game. Five notable candidates include:
1) Glare - Designed to navigate dark areas and alert players to hostile entities.
2) Penguin - Envisioned to inhabit stony shores and provide a speed boost while navigating boats.
3) Rascal - An elusive mob that resides below y=0 and rewards players with rare items upon discovery.
4) Crab - Proposed to thrive in mangrove swamps, could be bred using kelp, and drops a large claw for placing blocks from a distance.
5) Vulture - Intended to circle over a player's demise location, marking where items lay for easier retrieval.