I would definitely pay for the game Concord, just for its brand.

If the sub title is Sony Flight Simulator

At least 90% of the memes and jokes are unrelated to the game, just no brain copy paste. That’s really annoying.

I like game-related memes, but they’re really hard to find now

KDE Connect: https://kdeconnect.kde.org/

I also use Resilio Sync. It’s not open source software, but it’s self-hosted https://www.resilio.com/

There are also open source sync services, like nextcloud or syncthing