I recently started a server using the Modern Beta mod with the "Beta Skylands" terrain generation. It's so fun to explore what feels like Minecraft from an alternate timeline.
Just looked up the map and I'm definitely gonna add it to my list things to check out. I've only been playing this game for 3 years and I feel like there's a lifetime worth of fan-made content.
I recently started watching Paladin Ryan on YouTube and he featured it in a video. It's so cool how you can have old seeds generate like they used to but with all of the modern features and content.