For the 'wow' factor, I find searching for interesringly named mods by TenPlus1 and Wilhelm, is pretty effective. There's a bunch of interesting monsters and creatures across their mods.
It's worth sharing that I learned from previous experiences modding Minecraft not to push my luck with too many mods at once. I had to unlearn that, for MineTest.
Since MineTest was built from the ground up for modding, I've found that I can have a ridiculous number (dozens) of mods running together without any issues, as long as they're bug free and up to date mods.
If i get the Minetest system right, it complains that voxelibre does not contain the default "mod" and player_api, that would mean i have to use most of those over default minetest "game" ?
Yeah, I found that a bit confusing. I think I've groked it, but I'm honestly not sure.
The game MineGame provides a variety of default mods. Most mods available in the ecosystem expect to run alongside whatever relevant default mods came with MineGame.
Some games don't come with some of those same default mods, and so some other mods aren't compatible with every game.
I can pretty confidently translate the error you listed as: "the mod you're trying to use requires another mod player_api, which is not included in the game you currently have selected."