I don't know of any, personally--while I've run some Katas online, it was always as part of a larger event (conference or company-wide event). I've suggested to Neal Ford and Mark Richards, who took up the katas as part of their architectural writing and speaking, that they consider running a few online, but I don't know if they've done that (outside of a hybrid or online conference--I think OReilly did one or two online a few years ago).
There used to be an Architectural Katas user group in Boston a few years back, but I've not heard if they kept it going--last time I tried to find them, it appeared to have shut down. :-/
I think, in general, you're best off considering building the group you want in your local area. There's any number of people who've facilitated them before, you can likely find one that's in a time zone that's relatively close by and have them facilitate online, for example, and that can get you started.
Good luck!