I don’t know how many of you will find this useful, but I sure like it. You can upload a .ctb or .stb file to this site and see what all the line weights and colors will look like. Then you can filter by color and lineweight.
(It’s Swiss, so you’ll see some French words. “Chargement…” means “Loading…”)
Bonus round: if you select-all once your .ctb is loaded, you can copy-paste to Excel (use “Paste Special…” to paste as plain text). You can paste several .ctb tables this way and do a side-by-side comparison of colors and weights. Handy when trying to work with another office’s plotstyles.