I have tried to make a small rigid body animation in Blender 2.92.0, where only one of the objects is floating, while still interacting with the other rigid bodies in the scene, that are falling normal. I have tried every setting in knew about, but I couldn't figure it out. I also tried to use drag but this resulted in all the objects floating, obviously. Their is also no information about such a approach on the internet (at least I couldn't find any). So im wondering if anybody knows a way to achieve this kind of effect. Thanks for your help!
It used to be that you could move rigid bodies into different layers and they would only be affected by the forces within that layer. This would allow you to create a force (such as Drag) which would only affect some of the objects. However, at later versions of Blender, that functionality is broken - see https://developer.blender.org/T87458.
Once that bug has been addressed it should be possible to have forces affect only certain objects by putting the objects in different Collections.