I'll contribute some random ideas to get this off the ground a bit:
- Greek themed. Wreath around the head, in some ruins, long flowy mane.
- Roman themed. Again within some ruins, possibly stood knee deep in a Roman bath with steam rising, could even be holding a bunch of grapes in the mouth.
- If you've seen Brave, you'll know what I mean by Will O The Wisps :)... Could be a fun idea
- If you're a disney fan, could base a horse on any of your favourite characters - their hair colour, where they live, what they like etc. Imagining a cute Ariel underwater scene or a cold, frosty Snow White theme with a juicy red apple.
- Could go anywhere with underwater, for example a seahorse :) the upper body of a horse but the lower body of an actual seahorse.
- Something dramatic like a horse rearing on the edge of a cliff or on a ledge near a waterfall. Wild winds, mane and tail everywhere, lightning about to strike the horse maybe. Maybe the horse has lightning markings already :)
- Some chonky RID art with wings. Haven't seen much of that around, so a pegachonk could be fun.