I’m not overly familiar with Houdini, but I assume, your Houdini scene holds a record of these paths somewhere? Can you use the Houdini API to find extract them in the collector?
If not, are the vdb and bgeo caches stored in a path that matches a template?
You could potentially use the core API to find the files if they match a template path. I can give more details on that, but I think extracting the path out of the current Houdini session would probably be better if possible.
Then once you’ve collected the items, it would be a case of modifying the publish hooks to publish those items. I don’t have any example code for exactly what you are asking, but our pipeline tutorial contains example code on how to write a custom collector and publish hook. Although it’s for Maya the concept is the same, you would just need to use the Houdini API whenever you needed to interact with Houdini instead.