Sure, youve got to pay the on the following turns upkeep, but Summoner's Pacts instant-speed casting means you can wait until the very last second before you decide what creature you need to pull
For example, if your graveyard contained Attack-in-the-Box (artifact creature) along with Shardmage's Rescue (enchantment) and Jump Scare (instant), you would have four card types among cards in your graveyard, and your delirium abilities would be enabled
Act of Treason, Act of Aggression, and similar spells to temporarily claim enemy creatures for your own use
For example, Averna, the Chaos Bloom lets you put an MTG land onto the battlefield tapped if you exiled it during your Cascade ability
This is a card that I'm going to want to play on turn four if possible
Modal counterspells have traditionally been quite good because, when counterspells are not good, the card still does something