You can tap Rosheen to add four generic mana to your mana pool, though you can only use it on spells and abilities with X in the cost
Kain, Traitorous Dragoon I dont know that Kain, Traitorous Dragoon is good, per se
This means early ramp spells are great opening hand keeps, as are mana rocks like Sol Ring or Chromatic Lantern
2 Swamp, By Piotr Dura A little known but nevertheless fantastic Swamp land, this Swamp was only included in the Starter Commander Decks
Assassin's Trophy offers most of the utility without the need to trigger delirium, and Eyeblight Ending is a dual-type (kindred / instant) removal spell that will even help trigger delirium
The poster child that showcases the flexibility of modal cards is Cryptic Command