Weird, somehow I've never heard of this species or seen one in another Star Trek series. From a cursory internet search that might be because I've never seen Star Trek: the Animated Series.
Supposedly the federation is a lot more diverse than humans with weird ears, noses or foreheads. Just that the old shows did not really have the budget and / or ability to make convincing, actually alien looking species. TAS can get around this by being a cartoon, modern shows use plenty of animation.
But even in TNG is a running joke about the cetacean officers that are always off screen of course. But supposedly there is a whole part of the ship under water where intelligent dolphins are doing their duties as crew members.
There's a running joke in DS9 about Dax having a thing for a man with a transparent head (so you can see his brain stuff). But of course we never meet this guy because they didn't have the CGI to actually make that.
Until ENT, the Andorians were kind of a joke/throwaway faction. Their original costumes were, shall we say, phoning it in. Blue paint, a very obviously antenna headband, some weird poncho things, and that’s kinda it. AFAIK, they weren’t ever shown on-screen at any time between TOS and ENT.
I don’t know the episode name, but I recall them being mentioned during the metamorph episode, I think she is named kamara or something.
At one point the ferengi (who try to steal her and have infiltrated the ship for that purpose) try to chat up captain Picard and the ambassador who is caring for her, Geordi takes them away to "show them the dolphins".