Depends on what you consider self-hosted. Web applications I use over LAN include Home Assistant, NextRSS, Syncthing, cockpit-machines (VM host), and media stuff (Jellyfin, Kavita, etc). Without web UI, I also run servers for NFS, SMB, and Joplin sync. Nothing but a Wireguard VPN is public-facing; I generally only use it for SSH and file transfer but can access anything else through it.

I’ve had NextCloud running for a year or two but honestly don’t see much point and will probably uninstall it.

I’ve been planning to someday also try out Immich (photo sync), Radicale (calendar), ntfy.sh, paperless-ngx, ArchiveBox (web archive), Tube Archivist (YouTube archive), and Frigate NVR.

Nintendo has repeatedly done things like this.

The original Wii supports GameCube controllers, the Wii U supports Wii Remotes, Wii U and Switch both support USB GameCube controller adapters, and NES/SNES Classic Edition Mini systems support the Wii Classic Controller. Switch Lite supports pairing Joy-Con too, despite having no rails for them.

Wii U goes so far with Wii Remote support that Nintendo usually treated it as the preferred way for extra players to join local multiplayer, moreso than its own Pro Controller. Wii games were more limited with GC controller but still supported it in a few big titles like Brawl and Mario Kart Wii.