I've created a repository with some custom openroad GUI scripts that I find useful and some test scripts to learn about the api.
The most practical ones right now are scripts to Load openlane or caravel design results, load intermediate openlane DEF files (placement, pdn, fast_route, etc), Load technology files
Here's is the repository if anyone wants to try it:
https://github.com/mbalestrini/openroad_useful_scripts