The cards first ability Good As New allows the player to exert Lucky, The 15th Puppy to reveal the top three cards of their deck, with every character card that costs two or less going into their hand and the others being put at the bottom of the deck in any order they want
Considering all possible card types in magic at the moment (the normal card types are artifact, battle, creature, enchantment, instant, land, planeswalker, sorcery, and kindred (ex tribal)), we get the maximum hypothetical size of Tarmo equal to 9/10
This means that, for example, you can't activate an equip ability between combats.
Bria, Riptide Rogue (BLB) $33.40 Bria, Riptide Rogue is a nice otter rogue that looks like its preordering at a high price, due to the fact that this card is only available in the Bloomburrow Arena Starter Kit, not Play or Collector boosters
Make your own Bitterblossom at home with some upside
The rest of the deck is filled with cards that either are creatures that modified themselves, have effects that let you modify creatures, or are spells that help modify your creatures