>>96582486
probabbly not gonna be relevant but there is a Monster called Zern in MM4 who are evil monstrous humanoids focused on using transmutation to turn others into monsters.
One of the Monsters they create is caleld a Zern Arcanovore, which is CR 7 and got the ability to use dispel magic at will and anti magic field 3 times a day. They are also explicitly noted to sell them to all kinds of other beings like fiends, mindflayers and evil mortals.