Shortly after launching AnkiReview, I added the Quicktags functionality. However at that time they were limited to 5 tags, which turned out not to be enough for my case. I recently made an update which gives the bottom bar a more compact look, and lets you define as many quicktags as you need.
https://play.google.com/store/apps/details?id=com.luc.ankireview
It's in beta currently, you need to be signed up for beta updates on the play store, or you could just wait for the prod release.