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
The ability resolves and deals damage to those creatures before combat damage is dealt
Then when I was working on Unhinged I used it as one of the abilities on Greater Morphling
Whispersilk Cloak - 0.75 vs
BATTLE ALONGSIDE ICONIC FINAL FANTASY HEROESJoin forces with Terra, Herald of Hope in the Revival Trance deck, Cloud, Ex-SOLDIER in the Limit Break deck, Tidus, Yunas Guardian in the Counter Blitz deck, and Yshtola, Nights Blessed in the Scions & Spellcraft deck
That's especially true in Commander, where the graveyard is simply another set of resources at your disposal, and even crucial for certain strategies