Specialty hobby shops and local game stores are reliable sources since they regularly stock singles, older sets, and sometimes even showcase rare cards behind the counter
Unless they play the 100HP Mewtwo from RUMBLE or attach an Expert Belt, Garchomp C Lv.X ( C) can answer a Mewtwo at least once, but the opponent can repeatedly try to get Mewtwo on the board which can be difficult if they also have other attackers or are disrupting you
They are: creature, land, instant, sorcery, artifact, enchantment, planeswalker, battle, and kindred
Because of this, it has become an excellent way to gain an advantage if your opponent hand traps you
Centering should be 70/30 or better
Milotic ex's ability, Sparkling Scales, prevents it from taking damage or being affected by the effects of the attacks of Tera Pokmon