Having a crapton of ANYTHING will slow your loading time. The game gets particularly frustrated when you have a lot of little files (like a mess of my hiders on GoS, or all 996 Front-Laced Lady gowns). You can shorten your loading time without culling anything two ways: One way is by texture-referencing anything that can be texture-referenced (which I'm in the middle of doing for myself), and the other way is to make sort of director's cuts-- combine separate packages into larger ones, for example, if you had my Pooklet'd hairs, you could not only delete a few grays (reducing file size), you could combine all sixteen hair colors into one big package (reducing the total number of files).

When I made myself a director's cut of hiders, I cut my loading time in half. (To twenty minutes, but then I use almost all of the three thousand hiders I made, plus a bunch of other people's hair and clothing hiders.) I'd advise starting making bundles of things that sort of already go together, like texture-referenced clothes bundled with their original recolor, or a Pooklet'd hair bundled all together. That way, if you do decide to cull something you've made into one big package file, you don't have to re-make the entire file and start over. (Also, always keep backups!)

There are some contemporary baby clothes by Theraven at Moonlight Dragon, but so far I don't know of anybody but me, Lilyturtle, and Theraven who's been making non-default baby stuff.