Fun and productive apps to use on virtual LANs
(Other than all the obvious things: SSH, SFTP, FTP, Apple and SMB file sharing, Bonjour/mDNS, etc.)
FireStr
FireStr (Fire★) is a platform for decentralized computing. It includes a number of examples including chat, draw, file transfer, voice chat, and a simple pong game. Using its API you can develop your own plugins to build decentralized mediums for collaboration.
iTunes
Built-in iTunes music library sharing works on virtual LANs. Share your music and others can listen to it! This is read-only, but check which libraries / collections are shared if you have private things you don't want others to see.
Git
Git, of course. With a flat virtual network Git can be used as intended -- as a peer to peer version control system!
ExpanDrive
ExpanDrive will let you mount almost anything, from SFTP servers to probably your toaster, as a drive on a Mac or Windows system. It will run over a virtual LAN just as easily as it will over a physical one, and often works better than the antiquated remote drive mounting protocols bundled with most OSes.
Fenix
Fenix is a beautifully designed user-friendly local web server for serving local files. Spin up a web server with Fenix and (as long as your local firewall allows it) users on virtual networks can see it. Use it to demo web sites or send files by sharing them via local web servers and sending users a link.
SubEthaEdit
SubEthaEdit collaborative LAN editing allows multiple users to edit the same document.
Dukto
Dukto is an easy to use cross-platform tool for transferring files and minimal chat over a LAN. It will auto-discover, so launch it and you'll see all other Dukto users on all the physical and virtual LANs you're on.
IP Messenger
Another open source LAN messenger / transfer app with both GUI front ends and command line tools.
D-LAN
D-LAN is another simple free LAN file transfer app.
VNC
VNC is a well-known app for remote desktop sharing. It supports remote control and a view-only mode for presentations and demos. Note that OSX 10.8 and newer has VNC built in as "remote desktop sharing."
Oort
Oort is still in early development, but claims to soon be "Your perfect edge router". You can install it on a VPS and it acts as a reverse proxy with auto SSL, as-well as a general proxy for various other TCP/UDP protocols. Its built on CodeIgniter4 and uses Caddy as its webserver. Automatic HTTPS is handled by LetsEncrypt. Its still a work in process, and will soon be ready to deploy. If you'd like to help out, you can join the discord here.