In my years of playing, I have seen plenty of judge calls because someone tried to respond to a Llanowar Elves tap
For the black ability, we were left with any of the other card types (artifacts, enchantments, instants, sorceries, and planeswalkers)
Legality depends on the tournament format -- Brock's Geodude G1 38 can be legal in some formats and banned or restricted in others
Zedruu the Greathearted, Blim, Comedic Genius, Jon Irenicus, Shattered One, and Inniaz, the Gale Force are the main choices for a classic hold my stuff deck
Spell/Trap or effect is activated, to gain 300 ATK x their Level, and finally to gain additional effects if they reach Level 7
The trap card, which can be activated when the opponent summons a monster, tributes that monster and one from your side of the field