General Mills collaborated with Pokemon to produce several promo cards that appeared in mini packs during their distribution periods, notably the Kanto Mini Packs from 2019 and the Sun & Moon version from 2017
First, identify your main goal
Being new to the hobby Im sure theres a lot of cards Im simply unaware of and dont have a huge collection to date, so a small pool to select from but would say the FA Blastoise ex from the 20th Anniversary set is probably whats surprised me most from purchase expectations (bought mostly due to price) to how it looks in person
For three mana, you get a 0/0 Green Creature that enters with two +1/+1 counters
This instant even contributes to the graveyard aspect of your deck if youre reaching for threshold, delve, or the like
Whenever a creature you control deals combat damage to a player, draw a card