Balance was in the core set since back in Alpha and Land Tax was an addition from Legends, but both were almost immediately put on the Restricted list as soon as it was released for Type II tournament play
You also get a stream of Saprolings, so that means you could make a few Saprolings each turn of rounds in a multiplayer game
You lose life equal to its mana value
The elementals that had the biggest impact on competitive Magic
It's on curve, cheap, in red that already loves Dragons, it's the color of Dragon enablers and ramp, and more
Energy turned out to be a very strong mechanic, and Aetherworks Marvel was eventually banned in Standard for being too good at casting Eldrazi like Ulamog, the Ceaseless Hunger on turn four