The also rans...

[Dragonhelm]

It's a misconception that thri-kreen are setting-specific to Dark Sun. While that's where they really shined as a race, they were in one of the Forgotten Realms Monstrous Compendiums prior to that. I don't know if they were in Greyhawk or not.

They're like drow that way. Drow were in Greyhawk, but the Realms made them famous.

 

[Serendipity]

I don't know if they were in Greyhawk or not.

They first appeared in 1983's Monster Manual II for AD&D 1e. Given that this was while D&D was still under Gygax's aegis, it can be presumed that they were indeed in Greyhawk in some capacity.