Humility (Tempest, 1997) Aside from having some of THE BEST art in all of Magic, Humility is one of the most effective ways to make creatures with big stats and powerful abilities more manageable
Any creature that gets sacrificed counts as having died , so sacrificing a creature will activate any when this dies triggers it might have
You can drop them early or free any time to break folks faces, and good free stuff is always good, but many in Commander might go with the 4/4 Wurms first in a Commander brew with 40 life to get too and trample too
In terms of specific synergies with the new cards, there are a number of notables
Because of the Masques Rebel chain, the Sergeant%%%Ramosian Sergeant%%% can begin recruiting 2/2 Steadfast Guards and other recruits as soon as turn three, who in turn can beat down or get even larger Rebels