Yes, you require transfer certificate and marks certificate of degree. Other required certificates are:

GATE /GPAT /PGECET score card or rank card or hall ticket.

12th or diploma marks certificate. SSC marks memo and original certificates.

Study certificate from 10th to Graduation.

Caste certificate.

Residence certificate of father or mother.

Income certificate.

Ration card.

Aadhar card.

https://www.appgecet.co.in/appgecet-counselling/

Visit this link to knowabout whether these things are mandatory or nor in pgecet.

The Andhra Pradesh State Council of Higher Education will be conducting AP PGECET 2018 counselling tentatively in fourth week of August. The counselling of AP PGECET 2018 will be conducted separately for GATE & GPAT qualified candidates and entrance test qualified candidates. The AP PGECET counselling 2018 will include process like choice filling, document verification, payment of fees, seat allotment etc. Candidates need to report to the notified Help Line Centres for document verification.

You can also visit this link for more info.