There are several robotics datasets for SLAM, like this one.
In this webpage you can see that the depth image is scaled by a factor of 5000, so that float depth images can be stored in 16 bit png files:
The depth images are scaled by a factor of 5000, i.e., a pixel value of 5000 in the depth image corresponds to a distance of 1 meter from the camera, 10000 to 2 meter distance, etc. A pixel value of 0 means missing value/no data.
I do not understand why this value is chosen. Why not simply 1000, so that there is a conversion of meters to millimeters?