Apart from Basculin (Rock Head / Reckless / Adaptability / Mold Breaker)
The Scolipede Family too has 4 abilities : (Poison Point / Swarm / Quick Feet / Speed Boost)
The Chandelure Family: (Shadow Tag / Flash Fire / Flame Body / Infiltrator )
This includes their pre-evolutions, i.e. Venipede, Whirlipede, Litwick and Lampent.
No other Pokemon have more than 3. ( the Legendary Dogs, despite ability changes stand at 3 each, and Gengar has Levitate and Cursed Body)
Also, as MM stated, these are changes between generations, probably to balance out their strengths. This is like the example Basculin mentioned in question. Otherwise, no Pokemon in a single generation has more than 3 abilities possible at a time.