On this topic, I think it is worth mentioning Framasoft [1]
It is a French organization that offers plenty of alternatives to Google and other big tech products. A lot of them are just rebranded and hosted open source software, but they also develop their own, such as PeerTube and Framaprout (the last one is a joke, but PeerTube isn't).
I hate to say it because it's cute but that website is not going to win over large companies to use these tools.
Yup, I'm surprised this wasn't mentioned earlier but they're the ones behind PeerTube (which I see posted on HN a lot) and many other tools. They've been building google alternatives for over two decades now and many of their tools are quite mature
https://degooglisons-internet.org/en/