Tax Keeper (Unknown Event #UG02b)

Tax Keeper {1}{G}

Creature — Elf Advisor

Tax Keeper gets +X/+X, where X is your highest commander tax among your commanders. (For example, if you’ve cast your one commander from your command zone twice, it gets +4/+4.)

1/1
Standard
Alchemy
Pioneer
Explorer
Modern
Historic
Legacy
Brawl
Vintage
Timeless
Commander
Pauper
Oathbreaker
Penny