Termux
Holy hell. So much it can do. Right now I am using it to transcode MPEG2 videos to AV1. With CRF 25, Preset 5, with a 480p30 video I get 5fps in Termux on my older Snapdragon 860. Meanwhile my laptop's Ryzen 3 3200U does 2fps.
You can run different server applications. Some are supported natively (e.g.: Tinyproxy, Privoxy, Squid HTTP proxy, apache2, nginx, navidrome, OpenSSH, TigerVNC, rsync, xorg-server, xwayland, xrdp,...) and some can run in proot (e.g.: Jellyfin, NextCloud). If you already have some web server and want it public, there's cloudflared too, so you can access it via Cloudflare tunnel.
RTL-SDR driver
Allows connecting RTL-SDR on Android and starting RTL-TCP server.
SDR++
The best general-purpose SDR app available on Android, GNU+Linux, Windows and MacOS.
KDE Connect
Nicely connects phone with a computer. Data transfers, remote control, finding your phone, synchronizing notifications.
LibreTorrent
Great client for Android.
There's more, but those I don't use daily, or have already been mentioned.
Termux
Holy hell. So much it can do. Right now I am using it to transcode MPEG2 videos to AV1. With CRF 25, Preset 5, with a 480p30 video I get 5fps in Termux on my older Snapdragon 860. Meanwhile my laptop's Ryzen 3 3200U does 2fps.
You can run different server applications. Some are supported natively (e.g.: Tinyproxy, Privoxy, Squid HTTP proxy, apache2, nginx, navidrome, OpenSSH, TigerVNC, rsync, xorg-server, xwayland, xrdp,...) and some can run in proot (e.g.: Jellyfin, NextCloud). If you already have some web server and want it public, there's cloudflared too, so you can access it via Cloudflare tunnel.
RTL-SDR driver
Allows connecting RTL-SDR on Android and starting RTL-TCP server.
SDR++
The best general-purpose SDR app available on Android, GNU+Linux, Windows and MacOS.
KDE Connect
Nicely connects phone with a computer. Data transfers, remote control, finding your phone, synchronizing notifications.
LibreTorrent
Great client for Android.
There's more, but those I don't use daily, or have already been mentioned.