In Dark Sun 4th Ed the feywild was canon, but its name was "land within wind", and also destroyed by defiler magic. This "land within wind" could be a joker card what would allow to add new things, as races (the wilden from PH 3 4th Ed or classes (warden and seekers).
In 3rd Ed the origin of the dragonborn was Bahamut the good dragon god chosen ordinary mortals as his champions against Tiamat, and they suffered a metamorphosys within an egg. And they were steriles. The dragonkin, dragonblood humanoids were canon in Faerun, even in 2nd Ed, but more powerful than ordinary dragonborns.
In Expanded Psionic Handbook the origin of the half-giants was as indirect allusion to DS. At least that was my opinion.
DS had got new and own genasi subraces: sun, sand, magma and cinder.
* After Baldur's Gate 3 DS would be one of the best candidates for an adaptation, but this will need a lot of work by "fashion designers" and artists because its look is unique.
* Now I am thinking there was a plan for a module set in Kalidnay, the dark domain crossover between Ravenloft and DS, since the beginning, not an improvisation al all. And in the end of the story Gwydion, darklord of Arak/shadow rift would visit Athas for a little time.
Other idea for a crossover is genies and sha'ir from Zakhara (al-Quadim) and Athasian elemental clerics discovering some planar gate to demiplanes within para-elemental planes, and different factions want to conquest that regions.