Nikon D50 has a Nikon F lens mount and currently there are 316 native lenses available for this mount.
Nikon D50 doesn't have a sensor based image stabilization system but 107 of these lenses already comes with optical image stabilization.
Since Nikon D50 has a APS-C sensor, it has a focal length multiplier of 1.5x so you have to multiply lenses original focal length with this multiplier to find the Full Frame equivalent focal length of the lens when mounted on D50.
You may also also be interested in these:
Nikon D50 Lenses with Image Stabilization
Nikon D50 Lenses with Weather Sealings