Speed is a slang term used to describe timing restrictions on different types of cards
Angel of the Ruins can handle some problematic permanents for good
Arthur is an incredibly powerful card that allows you to earn lore with your weak questers like Lilo, Making a Wish and Pinnochio, Star Attraction, then bounce them back to your hand to keep them safe from challenges - while also rewarding you with two lore for doing it
Any of the "whenever a card leaves your graveyard" enablers, from Teval's Judgment to Syr Konrad, the Grim to On Wings of Gold, are crucial to Varina
This allows a trainer to not squander precious cards
Its reminiscent of a Turntimber Symbiosis thats just kind of worse on both ends, but getting a big creature out of a land is fine late-game utility, especially when you get the land back anyway