Linux Command Library is a Android app that works as a manual for Linux commands, something like tl;dr or manpages but for phone with GUI and can directly search for categories such package manager tools, ssh, git, etc.

The neat part of it is that you don't have to guess a command, for example, if I want to descompress something (and I don't have internet connection) and I don't know the command I'm pretty much fucked, I can use the manpages but first I need to know the command to use it.