There might not be many of them (seven in total), but now that I actually have a chance to play with them, they're kinda neat.
Not gonna lie. I think my early favorite is the GC III logo. Until we get actual Faction Specific logos in, I think I might get heavy use out of that one. Did a quick addition to my custom Cargo Survey Ships, and it looks like this at the base level without anything else attached:
(Yes, I intentionally have it designed to look like a locust on the main map. It just gives me a little thrill to see a swarm of them all over the map. )
I think my second favorite one is the "hooded engine". Simply because it is so different from everything else.