Xmind - Xmind is a brainstorming and mind mapping application.
Documents by Readdle - A central hub for all your files.
MindMeister - Create, share and collaboratively work on mind maps with MindMeister, the leading online mind mapping software. Includes apps for iPhone, iPad and Android.
Filza File Manager - Explore files and folders with list view or grid view. View / edit files with powerful viewers.
MindManager - With MindManager, flexible mind maps promote freeform thinking and quick organization of ideas, so creativity and productivity can live in harmony.
FE File Explorer - The one-stop files solution