I’ve been using FX File Explorer since 2012. It’s straight up the best file manager on Android, especially when you use SMB and SFTP. Multi window makes moving things around easy as, and the built in text editor works a treat. Being able to share images from apps to FX’s “Save As” option is awesome to. It means every app can save where you want.
No idea why it isn’t more popular compared to the alternatives.
TickTick
https://ticktick.com/features
It’s what Wunderlist used to be like before Microsoft bought them and buggered it up, but keeps getting improvements.