Late to the party, but…
In an old homebrew, I did an insectoid race based on thei-Kreen, but who were Small, and had aspects of dragonflies and lighting bugs. As such, they were highly maneuverable fliers and could communicate via bioluminescence. While the size & flight might not appeal, the bioluminescence opens some interesting RP and mechanical possibilities.
(Similarly, with communication via chemical markers so common in the arthropods, perhaps THAT could be of use as well.)
Or perhaps, something with a centipede/millipede morphology, as a riff on the Caterpillar from Alice in Wonderland as a trippy dispenser of wisdom. I could see them as consuming toxic and psychoactive compounds and metabolizing them to actually gain insight into reality. Perhaps like DC’s Swamp Thing, they become more attuned with nature. Or maybe some kind of magical clairvoyance occurs.
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On the tentacles front, I seem to recall there was a humanoid being early on in Clive Barker’s Imagica that had long, slender tentacles protruding from its back very much like the Marvel Comics villain, Doctor Octopus.
Or something more amorphous? Something that can project pseudopods. A quasi-humanoid mass of brain cells that physically synapses with (touches) other beings to communicate…