I really like Quagsire in this format, however, you should be aware that even with maximum investment, a full health quagsire still has a considerable chance of being 2hko'd:
252+ Atk Choice Band (custom) Brave Bird vs. 248 HP / 252+ Def Quagsire: 187-222 (47.58 - 56.48%) -- 32.03% chance to...