Olympus E-1 has a Four Thirds lens mount and currently there are 45 native lenses available for this mount.
Olympus E-1 doesn't have a sensor based image stabilization system but 3 of these lenses already comes with optical image stabilization.
Since Olympus E-1 has a Four Thirds sensor, it has a focal length multiplier of 2× 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 E-1.
You may also also be interested in these:
Olympus E-1 Lenses with Image Stabilization
Olympus E-1 Lenses with Weather Sealings