I have a fitting that I think is a metric pipe thread. It is tapered.
I have seen some charts on the web, but they are just for identifying parallel threads, not tapered threads. For example, these charts just have one "outer diameter" listed for the thread, but obviously each thread has a different diameter if the thread is tapered.
In the case of my fitting, it has 5 threads in 9mm or 11/32" which does match the pitch of any pipe thread that I know of.