There is Mobile applications from RESCO and CWR Mobility
1. RESCO
You can download Mobile App(Android, iOS ,Windows) form below link
Resco Mobile CRM for Dynamics
You can use and check it free only for Built-in entities
but for custom entities and other full feature see
Pricing
2. CWR Mobility
CWR Mobility
3.Resco VS CWR Mobile
there is also blog with difference RESCO Mobile VS CWR Mobile
comparision Resco Vs CWR Mobile
I hope it help you
Muhammad Sohail