Termux yeah. I use it everyday. So here is a (long) list
Use ffmpeg to convert videos or even edit it(with current 6.x version, mediacoded hwaccel is availiable)
yt-dlp
Use vim and emacs, maybe code something
Integrate it with other plugin apps like Termux:API(lots of system apis), Termux:Boot, Termux:Float(floating terminal), Termux:Widget, even Termux:X11 For running gui apps
You can run gui apps with other X servers like XSDL
Compile and run programs that is not availiable for arm(Worst thing, but i still does it. Much hassle and error prone, but fine for smaller programs)
Use ssh to connect to other devices
Install x11-repo and thus install xfce and firefox desktop(for fun)
Install proot-distro and use distros like debian, arch, ubuntu, manjaro, void, fedora, etc. which is cli only by default but you can install any DE.(You can combine display server from XSDL)
Use git, clone a repo, make changes, use it or push commit, whatever you do with git
Use your normal standard linux commands to browse thru your filesystem and make changes
neofetch, cpufetch, rxfetch, htop, gotop, cmatrix and hollywood for lolz
tmux, byobu or gnu screen
Tar, gzip and all coreutils
cryptomining(DON’T do that)
Test your webpage locally (php -S localhost:port)
Ahem I wasted a lot of time making this list i think i have to go now lol