First of all, he can't be the target of spells and abilities your opponents control, meaning he's pretty tough for your opponent to deal with
No, there arent any other one-of-one serialized cards, but there are two unique cards
Cryptid Inspector Two generic, one green creature Elf Warrior 2/3 Common Vigilance Whenever a face-down permanent you control enters and whenever Cryptid Inspector or another permanent you control is turned face up, put a +1/+1 counter a Cryptid Inspector
Once you find that, it gets easier
After a long day at school and work, before Fergals, Jethros were only Sherwins
Engle null/null NOT LEGAL Standard NOT LEGAL Future NOT LEGAL Historic NOT LEGAL Timeless NOT LEGAL Gladiator NOT LEGAL Pioneer NOT LEGAL Explorer NOT LEGAL Modern LEGAL Legacy NOT LEGAL Pauper LEGAL Vintage NOT LEGAL Penny LEGAL Commander LEGAL Oathbreaker NOT LEGAL Standardbrawl NOT LEGAL Brawl NOT LEGAL Alchemy NOT LEGAL Pauper Commander LEGAL Duel NOT LEGAL Oldschool NOT LEGAL Premodern NOT LEGAL Predh Enchant player Whenever a player attacks enchanted player with one or more creatures, that attacking player may discard a card