I do not use the phrase "Indo-Tibetan." I'm not sure what should be implied by that name. It is my opinion that many or most zi beads were made in India—and that some of these beads, such as those you show, have a much wider range of occurrence throughout Asia. (Well beyond India, but probably exported to these places from India.)

I am not aware of any Tibetan (nor Indian) names for these specific beads. Some people refer to them as "chung" (or "chong") beads. I limit that name to certain beads, such as the carnelian zi you show, that you also call a chung zi.

Attached is Plate III from my 2002 article on zi beads, showing the beads we are discussing (as well as others). I refer to these as striped or banded zi beads (when they are derived from Tibet or the Himalayas). This particular photo is harvested from my FaceBook page, when I was discussing zi beads a few years ago.

JDA.