I love this! Especially a buffet of slaad. I'd like a side of green slaad with that.
Here are some others off the top of my head.
A "hoot" or "hootenanny" of owlbears
A "glamour" of displacer beasts
A "tangle" of grell
An "embrace" of ropers
A "network" of chitines (or other spidery things like ettercaps)
An "enigma" of sphinxes
A "roar" of liondrakes
A "cacophony" of kenku
I can get so distracted with this activity. Time to take a break for now.
A clowder is a group of cats, but you can use "clouder" because they fly.
A "pride" fits for the lion part, and "convocation" is used for eagles, but maybe you're hoping for something unique?