Why are so many mods not in the mod list?

I’ve recently noticed that, in the experimental builds (0.C-6421 at the time of posting, but this may be true for others before and after) there are several mods in the mod folder that don’t appear in the mod list when you’re creating a new world (DinoMod and Animatronics to name two examples). Why is this the case and how do I change this?

Many of them are obsoleted, that means they are there for old worlds who use them to not break but are not available to be used in new worlds. You can revert this by going into the mod folder of a mod you want to use and go to the modinfo.json and set obsolete from true to false.

Plus many were cherry picked for best stuff and added to core game. =)

and some make no sense to still be in, like fast/slow zombies and weak/hardy zombies since there is now a 1-200% option for both speed and health stats for them.