Right now there's 22 Generated cards, 14 Monsters, 2 spells and 2 Artifacts that can generate cards. -Beta 28.0
MONSTERS: Annoying Dog - Adds Dog Residue to the opponent's hand after you play it. Gift Bear - Generates Gift card at the end of its owner's turn. Bunbun - Generates Bun after you play it. Dad Slime - Summon two Kid Slimes in the board upon death. So Sorry - Adds 2 Doodlebogs to its owner's hand. Rock - Generates a Pebble upon death. Dancer Mettaton - Generates Mettabot whenever Dancer Mettaton attacks and kills a monster. Temmie - Adds Temmiy (aka Temmie 2) to its owner's hand upon death. Snail Trainer - Adds Thundersnail to its owner's hand if there's 2+ ally snails. Onion-San - Generates 2 Tentacles adjacent to it. Angel of Death - Fills empty slots with random Lost Souls upon death. Sans, Gaster and Lost Soul 3 - They add Gaster Blasters. Sans and Lost Soul 3 add them to your hand, while Gaster adds them to your deck. Omega Flowey - Saves the Board and adds Load spell to your hand. SPELLS: Sacrifice - Adds a random Lost Soul to your hand after killing an ally. Octofriend - Summons both Tentacles adjacent to selected ally. ARTIFACTS: Science - Adds 5 Gaster Blasters to your deck. Also makes ANY Gaster Blaster you cast deal 1 bonus Damage. Mines - Adds 1 Little Mine, 1 Mine and 1 Big Mine to your opponent's deck at the start of the game.