A way to add custom filters not specific to fields

In graphene-sqlalchemy-filters. One of the benefits was that when adding custom filters, they didn't have to be associated to fields. It seems the new filter setup covers 90% of the use cases which is great! But, having custom filters unassociated to fields would be amazing. Are there any plans to support this?

I mention a potential solution in the discussion here
https://github.com/graphql-python/graphene-sqlalchemy/discussions/408