Onshape has developed a lot since Keyshot plugin was published. Today it is not enough to be able to access documents and workspaces.
Plugin should search / browse also:
- Document Folders
- Document Tags
- Document version / revision
- Tab folders inside document
- Part studio configurations
and hopefully soon Assembly configurations.
Also Scene units (https://www.keyshot.com/forum/index.php?topic=21595.msg91992) issue should be adressed.