Umm not much sadly… Most Syriac Theologians (at least in the Syro Malabar church) are considred hertical
But some primary ones are:
Mar Aprem (St Ephrem the great)
He is especally honored in the 2 churches and his songs too, are held in great esteem (though most are not translated)
Mar Babai
While he isn’t revered in the Syro Malankara church, he is in the Syro Malabar church. His song, Sagdinan Mar, is especally popular
Mor Jacob of Sarugh
This theologian is pretty popular among the Syro Malankara’s but not in the Syro Malabar church
Modern theologians:
Fr.Placid Podipara
A saintly priest who helped rebuilt the Syro Malabar church and delatinise it. A model like him is NEEDED! He also helped establish the Syro Malankara church. Fr.Placid primarily wrote about Nestorianism and how it was compatible with the Catholic church. He also wrote about the Syriac Orthodox theology and is also highly respected by them. Mar Aprem Mookan would be his Assyrian counterpart. Works by Fr. Placid are:
Mariology of the East
(I’ve read this short book. I suggest you too, should read it. Great insight.)
Wikipedia has a whole list of his books. Most of his other works, I have not been able to read.
Pope John Paul II
-The theology of the Body is very famous among the Syro Malabar church and so it is taught in all CCD 12 grade classes. I would dare to say that without this book, many Syro Malabarians would of fell astray