Cards that prevent creatures from untapping, as these are so disliked by the majority of players that resolving one actually gets more combat damage dealt your way, not less
As long as you attacked with three or more Merfolk this turn, Merfolk you control get +1/+0
Merfolk It might be cheating a little bit to include three cards, but I do so because I think any one of them individually would probably not be enough to really push Merfolk's power level
If the creature with mentor leaves the battlefield with the mentor ability on the stack, use its power as that creature last existed on the battlefield to determine whether the target creature has lesser power
Modern Horizons 3 Collector's Edition Commander Deck - Tricky Terrain $319.99 US Shipping Only Due to export restrictions, this item may only be shipped to addresses in the United States, APO/FPO addresses, and Puerto Rico