Question: best to do list app for kindle fire?
Answer: Any.do. (Free + IAP) ... 
Todoist. (Free + IAP) ... 
TickTick. (Free + IAP) ... 
Tasks.org. (Free + IAP) ... 
One List. (Free) ... 
Suru. (Free) ... 
Google Keep. (Free) ... 
Google Tasks. (Free) A simple Google Tasks manager, available for iOS and Android.