How to use template_ID_preview on custom data?

Hello

I am interested in creating a library of assets using Blenders Template system. The problem is that “template_icon_view” does not have SEARCH bar however “template_ID_preview” does. Problematically template_ID_preview requires Blender ID types which is where things are getting a bit confusing for me. I am yet to find a custom example of such a script that does not use built in blender data IDs.

Example: Suppose I’d like to load Custom HDRs into Blender by first going over a folder of say 200 thumbnails. HDR’s might be tagged such as “sky, interior, outdoor” which is where searching will become handy.

In short, need searchable CUSTOM asset as such:

PS: custom input field that limits data on update is not a viable solution. Ideal solution is to get template_ID_previews working with dynamically generated custom BlenderID data types.

Very appreciative for help!