SEA ELF
VS ASTRAL ELF
First, Sea elf, one of my favorite elves! They're amphibious, human-sized, observant, can talk to sea animals, and are actually really friendly. They don't understand why land elves are constantly arguing about who's best and hierarchies and such. They live in the sea, where more friends is always important to defend against krakens and such. And despite this artwork, GENERALLY they tend to be much heavier than other elves and have deeper voices.
On the other hand, Astral Elf, human sized elves that went to the astral plane to be closer to thier gods. A land where nobody ages, so they're ancient and melancholy and broody and bored. They can teleport, see in the dark, create dancing lights, and are quite perceptive! Thankfully some stave off apathetic depression and existential dread. They do this by going super hard into a passion! So some of them are just super big into mapping the universe, or mastering all the arts, meditation, etc.