Custom Post Type and Taxonomy Query Plugin

I am having the most difficult time finding something that will query custom post types and taxonomys by SLUG. The only one that did this was SRP Pro, but it is not responsive and does not even use AJAX for pagination, so it isn’t something I can use.

Rather than query on the slug, it seems all other plugins query on the ID which is not controlled, so if you do any dynamic calls to match up values and return if a certain condition is true, it is not possible without doing a cross list lookup.

Any ideas?