The Aboleth is a bit of a staple in TTRPGs especially DnD 5e. That being said I typically see the Aboleth being used as a one off encounter for the party to typically find a way to escape from. Now that is in no way wrong but the Aboleth can be so much more grand than that. You could quit literally build an entire campaign around the Aboleth. In the age before gods the Aboleth ruled over the seas like they themselves were actual gods. They were immensely powerful and had people worship them. During the age of the gods the ACTUAL gods saw them as a threat and killed them off, the only problem is Aboleths can't actually die. If their body dies their soul returns to their natural home on the Elemental Plane of Water where they grow a new body. The Aboleth has multiple lair actions and contort the area around their lair. They can telepathically speak to people and read their thoughts promising rewards that are catered to the victim and even make them believe they received said rewards after doing its bidding. The Aboleth is an incredible Lovecraftian esc monster that can add some incredible depth and story to a campaign. Thank you for listening and be safe adventurers, but of course, not too safe.