I believe book writers, composers, and lyricists are all part of the Dramatists Guild, which is not technically a union for a few reasons (although it more or less functions like one).
I don't know about set and costume builders. If you mean designers, they're under USA (United Scenic Artists). Pretty sure that covers costumes, too. If I'm wrong, someone please correct me.
Also, SSDC dropped an S. It's just SDC now. Not sure which S they dropped, though.
There are other unions, too: ATPAM (company managers and ushers), hair and wardrobe crew (it's a local, I forget the number), and Teamsters (the crew that transports sets and stuff for load-ins and load-outs).
Probably more, but those are the big ones.
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