You kind of always have to go on a quest for a library on the internet, why would lua be any different? For lua, luarocks is its module registry and you can sort by most downloads, which sometimes leads you to buggy modules, but what can you do.
There's nothing stopping anybody from making a batteries included lua, and plenty have done so (emilua, luapower, luaforwindows, luart and etc), of course, pure lua still exists and their changes are usually backported into lua since its so small and portable.
FWIW you can do a lot with pure lua and unless you're importing json there's no reason to include a library for it given that lua itself can be used as the data exchange format.
