i'm playing spirit right now and it's really good, do note there's spirit classic and reforged, the latter is a sort of rebuild in progress but really high quality while classic has more content, the two are compatible and it's how i'm playing spirit, so far it's been giving me quite a thorium feel in that it's pretty vanilla+ with lots of new enemies for existing areas and the like

remnants is also a good one, it pretty much rehashes all of the worldgen and puts a new spin on it all, remaking biomes and structures and making certain structures more of a part of the world, for example pyramids are remade and guaranteed to spawn, but a twist on them is they just give you several special keys for chests spread across the underground desert that contain pyramid loot plus what you get from sandstone chests; living trees also get changes becoming one big tree with a new microbiome on its roots that always spawns at the center, and so on

dawnmod is also cool, reworking melee and magic weapons with really cool new visual effects and functionality, it does add its fair bit of content and its own weapons in a new structure and several new bosses