There are four Churches which worship according to the East Syriac Rite - two are in full communion with Rome and two are not - but all four have “valid” sacraments / apostolic succession:
The Chaldean Catholic Church - in communion with Rome
The Syro-Malabar Catholic Church - in communion with Rome
The Assyrian Church of the East - not in full communion but there is an agreement for limited inter-communion under certain circumstances
The Ancient
Church of the East - not in full communion, no inter-communion agreement to my knowledge
The Chaldean, Assyrian, and Ancient Churches of the East are very small. The largest East Syriac Church by far is the Syro-Malabar Catholic Church which is primarily based out of India.