This feature could do with a little work.
I think I have 2 collections starting with K, so just typing K and being presented with those 2 collections would be really nice (Just using Ctrl+F works much better at this point, but still not great).
Also, if I try to add a model to more than one collection, it only adds it to the last collection selected (if using the search function to find both collections).
Also, also, please add a similar feature to Bambu Handy.
Unrelated, but please enable panning on 3D model previews on MakerWorld, by dragging with the middle mouse button 