I am running 62 non-lands, and then a few modal spell/lands to up my spell options while not hurting my various things I am focusing on
The grind to get all the cards and reach Level 50 yourself is easier if you duel many opponents who own high-level Decks (which is the only real reason why opponents have Levels in the first place)
Umaro, Raging Yeti* Straight to you from the World of Ruin in the Revival Trance Commander Deck, Umaro is a beast of a design as a 6/6 for 6 with trample who will either pump your board, shoot something, or wheel you each turn at random
Mega Lucario ex #179 ($278.07) Secret rare with alternate aura art, this Fighting ex synergizes with Trainers
Super Express, which turns around cards in 710 business days, costs $349 per card
The Timeline of Banned/Restricted Cards on the GamePedia MtG Wiki