Panasonic G100 has a Micro Four Thirds lens mount and currently there are 107 native lenses available for this mount.
Panasonic G100 doesn't have a sensor based image stabilization system but 31 of these lenses already comes with optical image stabilization.
Since Panasonic G100 has a Four Thirds sensor, it has a focal length multiplier of 2x 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 G100.
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Panasonic G100 Lenses with Image Stabilization
Panasonic G100 Lenses with Weather Sealings