Solid Explorer is the nicest looking file manager with two independent panels which brings to you a new file browsing experience.
Amaze File Manager
Amaze File Manager is a free and open source file manager for Android with zero in app purchases.
FX File Explorer
FX File Explorer is a free file explorer application for Android.
A minimalist file manager for Android 4.1 and above that is free to download but includes in app purchases that range from $1.00 - $20.00 per item.
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