I use an NFS share to transfer files and keep work in one central location, but a true copy-paste store across devices would be interesting. You'd have to be able to sync the clipboards across many devices, so to I'd either propogate updates in a similar way to routing protocol daemons, or go with the less flexible but easier to set up clipboard daemon->ssh-and-xclip. It would probably be wise to use a VPN like wireguard to maintain some level of security and confidentiality.