Time to look at the aberrations that receive significant updates in Monsters of the Multiverse. Most of these are spellcasters; the exception is the star spawn mangler. These changes aren’t tactically earthshaking, but they do require certain things to be prioritized differently.
First, the neogi master. It gains a new attack action, Tentacle of Hadar, a hybrid of arms of Hadar and eldritch blast with a range greater than the former and less than the latter. Its Multiattack is modified to allow it to attack twice with this action as an alternative to Claw/Bite. As for its Spellcasting ability, it loses access to arms of Hadar, counterspell, fear, invisibility, unseen servant, eldritch blast and vicious mockery. It can cast its remaining leveled spells once per day and its remaining cantrips at will. Finally, Enslave, formerly an action, is now a bonus action.
Because Multiverse monsters no longer have pact magic, the neogi master can cast hold person at only one target at a time, whereas before, it could target three. This loss hurts, because the neogi master can no longer paralyze both the target it wishes to enslave and the tough front-liners who come to its defense—and the concentration requirement means it’s still constrained from casting hunger of Hadar at the same time. A neogi master now needs a posse of regular neogi to lock these characters down, whereas before, it could have worked alone.
On the other hand, thanks to the Multiattack upgrade, a neogi master no longer has to get within melee reach to attack. The one-two Tentacle punch makes the neogi master a more effective skirmisher than it was before, able to switch back and forth flexibly between short and long range. Also, the loss of other combat actions narrows the focus on what was probably meant to be central to the neogi master’s tactics all along: hunger of Hadar, a damage-dealing sphere of magical darkness into which the neogi master can see, thanks to Devil’s Sight (which it always had, although it wasn’t called out explicitly as a trait), and therefore use Enslave. In fact, since Enslave is now a bonus action, it can even combine the two on the same turn. The caveat is that, while hunger has a 150-foot range, the range of Enslave is only 30 feet, so the neogi master can’t execute this combination from farther away.