Is there any reason for not using other divine beings from other mythologies like Hindu Devas and Shinto Kamis? Maybe they're too human-like but I believe the same could be said about the Sidhe.
If they're not meant to be playable, maybe the Eastern type of Dragons could fit the bill? In the real mythology they are said to have power over the weather, you could expand it into fantasy by saying they're the caretakers of the natural laws.
For something playable, Insect Men seems fitting. If based on more social species like Ants it's easy to see how it relates to their ceremonial customs and formalities, and the control it implies.
You could also take a look at the mythical
Nommo from the African mythology. They are referred to as “Masters of the Water”, “the Monitors”, and "the Teachers". A Merfolk along these ideas, maybe mixed with the myth of Atlantis (and visuals from Aquaman movie) could be interesting as well.