They can still be used in casual play, draft, and sealed formats .
While Mystic may be more powerful than some of the others it is somewhat less unique in blue
Usually you are wanting to hit dorks with your bounce, certainly it vastly reduces the utility of the card having only creatures as potential targets but it doesn't much affect the power
What this puny 1/1 does have is a flying keyword that makes it hard to block - and a proliferate ability that triggers every time it deals combat damage to a player
Youll run into: Tokens (usually standard size, but occasionally printed in other sizes depending on product) Emblems and checklist/helper cards (standard size) Oversized cards (promos, special products, Planechase planes, Archenemy schemes, Vanguard, and other delightful chaos)
(3/19/2021) The card types that can appear on cards in a graveyard are artifact, battle, creature, enchantment, instant, kindred, land, planeswalker, and sorcery