Hey yanz welcome to AF!
I too love ES File Explorer..
some of my other favorites are...
- an ebook reader with cool features.
musiXmatch Lyrics & Music
- a music player with lyrics for all your songs, I found this app to be particularly battery friendly when data is turned off compared to other music player apps.
Titanium Backup ★ root
- an app that requires root but should be an essential to all root users.
FoxFi (WiFi Tether w/o Root)
- I've used this app for months to tether my pc for interwebs