I found this server called VoxaGens and it seems pretty chill.
The owner really wants people to try it and give thoughts about it. They are looking for players who will join and see how the server feels and maybe say what could be better.
If you want a place to hop on and just see what someone is building for a Minecraft server this one is open for that. It feels like they actually care what new players think.
There is not a lot of info about rules or gamemodes but it sounds like a simple server where your opinion matters and you can help shape how it turns out.
