There’s quite a lot of speculation around the actual number. This site is good if you want to check for any you may be missing, although they do say they are not a complete list but its the best I’ve found.
Also, I don’t know how dynamic the number of dyes is going to be. For example there’s Pink Day in LA on the 20th Oct and then the Halloween event and maybe Anet will add new dyes for these events or for events in the future.