Formations Overworld adds a bunch of new structures to the various Overworld biomes, giving you more to stumble upon while exploring.
Made by SuperMartijn642, it runs on NeoForge, Forge, Fabric and Quilt for Minecraft 1.20 - 26.3, and the author allows it in modpacks.
Give your group more reasons to explore: put it on your Minecraft server with one click from the panel.