I love this idea, which feels like a twist and refinement on the Bloomburrow Expend Mechanic (except you've got to pay it all on one spell), and anything that sweetens the pot when it comes to casting big instant and sorcery spells sounds good to me
Witherbloom and Lorehold both lean heavily on synergy, requiring multiple pieces to function at full strength, such as life gain plus payoffs or graveyard interaction plus enablers
Land Color tag templates(None) Marsh Flats , Pay 1 life, Sacrifice this land: Search your library for a Plains or Swamp card, put it onto the battlefield, then shuffle
Titania, Protector of Argoth
Nadaar might seem weird given there isnt much other dungeon synergy in the deck, but the Initiative can provide such value over time that you really just want to get it on the board
It's handy for combo strategies, builds your Storm count, pumps Prowess creatures, puts an Instant into the graveyard to get you towards Delirium or enlarge a Tarmogoyf, and gets you closer to Threshold or pays for Delve costs And sometimes you would rather have cards on top of your deck than in your hand