Aboleths are weird primordial fish creatures - they are also pretty exciting to create a campaign around. They once held an ancient empire, but are now in hiding as they regain their numbers and increase their power, their plots slowly churning to retake their lost lands. This time, I'm adding something new, which is a short paragraph on the tactics that a monster would employ in a fight.
Aboleth Fry (CR 6) The lowliest of all aboleths, those just hatched from their eggs. They are rather weak (compared to their adult versions) and are often treated as disposable pawns in the aboleth political structure.
Aboleth Psychic (CR 14) With powerful mental abilities, the psychics are near the top of any aboleth hierarchy. They can attack and obliterate the minds of their enemies, and so there are few who would openly stand against them.
Aboleth Master (CR 23) No hierarchy would be complete without a ruler who oversees it all. These are the most powerful of all aboleths, who rule with an iron tentacle. Their intelligence is constantly tested by all the others, and so they must have the greatest powers or be overwhelmed by those below them.
Skum Overlord (CR 9) Skum are some weird creatures. When they were first introduced in 3e, they were weird frog-like humanoids, and then they become strange and slimy octo-humanoids. Regardless of their shape, they have an overlord who rules through violence and pain, commanding those below it and not caring for their safety.
Thrall Template Maybe you want to create your own aboleth thrall army, with this easy template, you can drop it on any statblock and have some thralls your aboleth can order about!