A fork of Graph89 with UI and UX tweaks and fixes for modern Android versions. Graph89 is an emulator targeting the Android platform for TI89, TI89T, TI92, TI92+, V200, TI84+, TI84+SE, TI83, TI83+ ...
I use this a lot and love it a lot! The ROMs it emulates are very powerful calculators.
Also, there is a new project that brings Qalculate! to Android. You can find it somewhere here. It's also a powerful calculator and is more integrated to the system because it's not emulation.
Most phone calculators lack things like graphs, statistical tests, etc. Really just for people who are quired to use Ti calculators or learned to use them in the past. Better apps imo exist (like numworks graphing calculator) if you don't have platform loyalty