Peer-to-peer file transfers in your browser Cooked up by Alex Kern & Neeraj Baid while eating Sliver @ UC Berkeley.
Using WebRTC, FilePizza eliminates the initial upload step required by other web-based file sharing services. When senders initialize a transfer, they receive a “tempalink” they can distribute to recipients. Upon visiting this link, recipients’ browsers connect directly to the sender’s browser and may begin downloading the selected file. Because data is never stored in an intermediary server, the transfer is fast, private, and secure. (Your PC must be online while the recipient download the file(s), if you shutdown the PC or goes offline, the download also stops)
You can selfhost it or use the official instance
KDE Connect should fit the bill; despite the name, you don’t need to be using KDE (or Linux even) since there are clients for every major OS, even mobile.
Among many other cool features, it lets you easily and simply just send a file from one device directly to another on your local network. I use it all the time to send photos from my phone to my desktop without plugging anything in, for example.