Stantler

Tackle and Zen Headbutt are both very bad moves, which are ultimately the biggest problems for Stantler. The former is better than the latter, and benefits from STAB. 

Stomp costs the least amount of energy, and benefits from STAB. Wild Charge is a powerful move and provides useful coverage, but is risky to use due to its self-debuff. Megahorn could be chosen if its coverage is needed, but demands more energy, and Bug-typing is typically not as valued. Return costs too much energy.