Hulk you might want to specify that you are interested specifically in UK carriers with VoWiFi feature working properly on Pixel phones.
I thought that might be a bit too restrictive to ask as I was expecting a big list & would happily extract what I needed from the bigger list rather than ask someone else to do it..
What I'm actually after is a list of UK MVNOs that properly support VoWiFi on Pixel phones. What I'm trying to dig down to, is why VoWiFi works on MNOs but not MVNOs. The GrapheneOS Usage Guide makes a couple of references to supported carriers, so I thought I could start there.
"officially supported carriers by Google."