Do you plan to switch from Adobe Lightroom to a different image management and raw editor, like its free alternatives darktable or RawTherapee? One of the main challenges is to preserve your carefully created collections‘ structure whilst migrating. Ideally via the file system represented by a hierarchical folder structure to be independent from whatever software you choose.
As I am currently abandoning Lightroom, I have written a Bash-script to accomplish this task:
For details please refer to the README.