Missed this thread. Apologies who had to lock my earlier thread (I suck at finding threads). Anyway, here's the set I put there.
Cubone the Tank @Thick Club
EVs: 236 def, 36 HP, 36 atk, 40 sp. def, 160 spd
Impish
Earthquake/Bonemerang
Knock Off
Fire Punch
Rest
I don't know why Cubone isn't used as a very defensive threat myself. 20 base defense and a decent HP stat isn't 2HKOed by a lot of things, especially seeing as Cubone has no common physical weakness. Some may say that he's easily out-classed by other walls as he lacks eviolite, but where other walls fail and are often set-up bait or free hazards, Cubone suceeds so not taking many physical hits isn't really so much of a disadvantage, as he needs very little time to cause huge amounts of damage. Even with a tiny attack investment, Cubone has an extremely high attack stat and is immediately threatening, capable of OHKOing nearly every grounded sweeper around. This can make him very tough to switch in as well as damage once levitators and fliers are out of the way. Earthquake, as mentioned, hits very hard on buckets of stuff. Knock off is very handy for things switching in like drifloon or bronzong. Fire punch lets him break opposing stall such as bronzong and ferroseed.