ClevNote - ClevNote is an amazing mobile application that helps you to write the daily memos on your smartphone.
Documize - Enterprise-grade wiki and knowledge management platform
Notes with pictures - Notes with pictures is one of the best mobile apps that enable you to write notes and add images, voices, videos, and attach documents to your records.
HackMD - Fast and flexible, real-time collaborative markdown, inspired by Hackpad.
Notepad by Splend Apps - Notepad by Splend Apps is one of the best mobile apps that enables you to create a to-do list and notes.
ReadTheDocs - Spend your time on writing high quality documentation, not on the tools to make your documentation work.