Don't mind me, just making a list of all entities that could be affected by this mod, while they aren't now

Bosses:
-Monstro (doing the large leap)
-Mega Fatty (doing the long leap; short leap is way to quick for the tell to have any sense)
-Peep (doing the leap)
-The Adversary (leap)
-The Bloat (leap and laser)
-The Cage (doing the leap)
-Monstro II (large leap)
-Gish (doing the large leap)
-Blastocyst (doing the large leap)
-Daddy Long Legs (both stomp attacks, along with the head slam)
-Mama Gurdy (doing the spike attack)
-Triachnid (both stomp attacks, along with the head slam)
-Sisters Vis (large leap)
-Bumbino (for the falling rocks)
-Reap Creep (for the falling rocks in phase 3)
-Lil Blub (doing the leap)
-Wormwood (doing the tail attack)
-Singe (doing the explosive leap)
-The Heretic (doing the multiple side-bite, laser attack)
-Mother (for the charge in phase 2, laser while switching between the phases)
-Ultra Greed (for the falling coins)
-Ultra Greedier (doing the leap)
-The Gate (laser)
-It Lives/Mom's Heart (laser cross)
-The Fallen/Krampus (Laser attacks)
-The Stain (tentacle attack)
-Hornfel (brimstone bombs)
-The Visage (lasers)
-The Lamb (charge, laser)

Monsters:
-Deep Gapers (for the brief moment before they emerge)
-Leapers (doing the large leap)
-Sticky Leapers (doing the large leap)
-Mr. Mines (for the brief moment before they emerge)
-Adult Leeches (when falling on top of the player)
-Tar Boys (doing the tentacle attack)
-Fat Sacks (when jumping)
-Quakeys (for the falling rocks)
-Mom's Hands
-Mom's Dead Hands
-Hardies (for the falling rocks)
-Slides (right before they charge)