Difficult, but Awesome: Rhongomyniad is designed to be this, as it requires the user to get several materials on board to be anything stronger than a 3000 ATK beater, which is more often than not impossible as it requires opening a near-perfect hand and your opponent opening no interruption
You may reveal any number of Water Pokemon and Water Energy Cards you find there and put them into your hand
What makes this one particularly good is that the initial cost is just two mana, and the fact that, short of Flusterstorm, your opponents wont be able to counter all of your card draw
This made the new Bug-type Elite Four member Aaron's team even weirder, and solidified Bug's sad status as a classification type, rather than an elemental one
All in all, this seems fantastic for Commander and has competitive potential
You name it