Different stores have different techniques, but it generally comes to down to something like Mint/Near Mint (M/NM) being the best followed by Slightly Played (SP), and Played (PL), Heavily Played (HP), and finally Poor
Legendary Creature - Human Warrior Cleric Commander (CTRL to add secondary) Anthem Jetmir, Nexus of Revels Creatures you control get +1/+0 and have vigilance as long as you control three or more creatures
That's usually enough to take that player from possible first place to last or dead, though this Dragon's admittedly mopey if you're at the highest life total
There are options outside of monowhite, too
MTG card sizes set the industry standard, but not every TCG shares the exact dimensions
I can see this card going absolutely insane in decks with a lot of enters-the-battlefield triggers based around creatures