While Karn isn't breaking anything and shouldn't be banned, if we ever get to the point where Karn, the Great Creator finds itself on the banned list (which is unlikely but not impossible), then Mycosynth Lattice would be 100% safe to unban
First, I can put my -1/-1 counters onto other creatures, either sacrificing one smaller creature, weakening a number of creatures, or greatly weakening one larger creature
Lets first look at Eelektrik NVI, a very popular Bench-sitter that also has 90 HP
Black Market Connections Black Market Connections allows you to trade life for resources each turn, and one of the options is to buy a card for 2 life
Performapal Whip Snake X EARTH Level 4 [ Reptile / Effect ] ATK 1700 DEF 900 Once per turn, during either player's Main Phase: You can target 1 face-up monster on the field
Nissa, Who Shakes the World brings the power by doubling down on your ramp plan while also generating threats or blockers