How to create additional product listing filters?

Greetings All,

I'm interested in coding a new product listing filter by category (similar to the Alpha2Product_filter contrib from Tibi), but really don't want to replace/mod the existing default_filter and accociated files as with the Alpha2Product_filter contrib.

I would like to design the filter to be either a dropdown, radio group or check box group by category or global. Would also include admin enable/disable and management of filter name / values pairs.

I have looked at the various files associated with the default_filter, and the Alpha2Product_filter contrib and feel I could create a new filter, just not sure how best to include the new filter in the product listing page?

Any direction / suggestions / code snippets to get me started would be greatly appreciative :clap:

I will share when done! :flex:

Thanks