Rounding out the age conversion trio is
Sweetdevil and
Kent Converts; they also do conversions for ages beyond teen and elder and have been active more recently than Simplex Sims (that still hurts I gotta admit)
Clothes:
Shokoninio and
Peacemaker for the boys,
Anubis and fallen hero Juliana Sims (blog with dead links
here, recovered stuff
here) for the girls. Speaking of dead blogs and reuploads, there was also
Modish Kitten and the actual longtime champ of custom content,
All About Style. The problem with the existing AAS reupload is no preview images, I can only recommend
searching on My Sims 3 Blog and matching up names. It's a large project to deal with, it was an incredibly prolific site for TS2, 3, and 4.
Shoes: no one but
Pixicat. The top post on her blog has everything in zip folders
with previews, it's a really nice sendoff on her part. Supposedly she's creating for Second Life now.
Hairs: I mean this does depend on your taste in hair textures. I don't like the textures that most custom hairs come with (and by that I mean "visceral hatred" but the meshes are great) and I can tell the difference even if some people cannot.
Pixel Swirl and
Beaverhausen are forever my unproblematic faves for hair textures that don't clash with EA's, though both of them moved over to TS4 a long time ago. No one's quite filled that void and new hairs/conversions from TS4 creators aren't stopping any time soon.
ChazyBazzy does a lot of TS4 -> 3 hair conversions now, with varying results (as she would admit) and retextures that fit someone's tastes.
Pandelabs does some converting and retexturing too, and
poisonfireleafs and
IfcaSims cover the rest for me. Completely unrelated, I use BuckleySims'
"Disentangled" hairs all the time. Part two
here, I love Buckley but her CC didn't quite fit into a tidy category.