I want to disable most of the base clothing from the game so that the sims have to select clothe from a smaller selection that I have assembled. Is there a mod for this or how would I accomplish this?

You'd have to make default replacement clones of the clothing you want to disable and uncheck the 'Show in Ui' flag to prevent it from showing in CAS or the dresser. You can also uncheck the enable for random flag to prevent it from being assigned randomly to townies and NPCs.

The available tools (CAS Tools and Sims4Studio) are set up to clone only one item at a time, unless Studio has bulk cloning functions I don't know about. (You can ask on their site) They're also set up to modify one item at a time. If you're comfortable with s4pe you could open the base game ClientDeltaBuild0.package in Program Files (X86)\Origin Games\The Sims 4\Data\Client and extract all the clothing CASPs to a new package and then change the flags on each one.

No matter how you do it it's going to be tedious, lacking a bulk clone and modify tool, which is actually not a bad idea.

BUT, there is a set of CAS hiders from MyIndieSims: http://myindiesims.tumblr.com/post/...-all-cas-hiders

I've never used it so can't say anything more about it.