Ask HN: Interesting SDN/VPN Projects?

I read Wireguard white paper lately and later discovered tailscale. This Software defined Networking/VPN kind of domain was really interesting to me and upon exploring further, I came across following interesting projects:

- tailscale (WireGuard)

- innernet (Wireguard)

- headscale (Wiregarud, control server for tailscale)

- nebula

- ZeroTier (virtual ethernet)

- weron (WebRTC for SDN)

What other interesting SDN/VPN projects are out there that you find very interesting/magical?

(edit to fix formatting)