To elaborate a bit, assume you were going to build two different mono-red decks
To be effective, the distinguishing mark or marks must be visible on the obverse sides of the cards, which are normally uniform
Invigorate plus Berserk can push an attacking creature into lethal range pretty quickly, and then post-combat sacrifice it to Minsc for the coup de grce
Conveniently, broken mana-sources usually lead to combos
Chaos: Whenever you roll Chaos, creatures you control get +0/+2 and gain trample until end of turn
Speaking of big creatures, if you are the rare green deck that doesn't have any, Khalni Ambush drops from great to medium or even bad, but since big creatures are more or less green's thing, it's hard to imagine too many green decks that won't get value out of the instant-speed fight spell