Dagsson's ability doesn't care whether or not the creature is actually sacrificed, only that the ability resolves with a legal target, and there's nothing at all illegal about targeting a creature that can't be sacrificed
In May, a single owner collection of Pokmon totalled 55,270
You can build powerful decks around this approach, using the idea of cycling, digging or searching through your deck with e.g
Once a dungeon is in play, you move through its rooms one at a time following the arrow path that connects the rooms
Know Infect plays as many as 10+ pump spells (not to mention Hierarch and Pendelhaven, and understand how topdecks or cards in their hand can turn a 1/1 Agent into lethal
What matters is spending one mana to their three or more