Some good late game removal that can't be countered is Blighted Fen. Drop it in once they bring out a large eldrazi. You have mana to work with at that point but some eldrazi can't be removed with low cost spells. Well this is a land card. Easy fix. You're also running with vampier +1 +1 Gleam of Authority is nice to jump into a large buff for any other creatures you have on deck. That is a side goal.
Id say get removal in your sideboard or at least tapping creatures. Suppression Bonds is cheap but for the meta go with Bound by Moonsilver

If you go with a stronger +1/+1 side instead of removal add Grasp of the Hieromancer Just tap whatever you want and use Gleam of Authority to add the bolser.

Thanks for the input! I like the Fen idea a lot, but I'm not concerned with ramping up the creatures, just getting enough individual triggers to whittle away at my opponent's life. One addition I'm considering for late game is Defiant Bloodlord, and I will probably sideboard in Grasp of Darkness and Call the Bloodline.