arceus pokemon card brilliant stars VSTAR Colorless / 220 / Basic Pokemon TCG: Sword & Shield

In all seriousness, this card stocks itself by exiling a creature you control and gives itself a weird version of Myriad when it attacks, making copies of the exiled card

Pair that up with a good amount of ramp (which is definitely easy to get in mono-green) and wraths or other ways to get rid of creatures

While prices have been falling over the past few months, near-mint copies of this variant sold for $12 in March

And while, as always, there are exceptions to these rules, hopefully they give you a great baseline to start from

Other effects that set its power to specific values that start to apply after the ability resolves, including future instances of the ability, will overwrite that effect