[WPMU DEV Dashboard] I need a plugin that will output posts based on keyword search

Ideally I could load such into a page via shortcode.
Features needed:
- loadable via shortcode (or php but ideally both)
- ajax pagination/load more
- templates (or at least styleable via CSS)

There are a lot of "post grid" type plugins that loop thru posts out there, but I can't seem to find one that ticks all these boxes.