Hi Harshit!

Revising through what you have studied in your Undergraduate Course will definitely help you in preparing for GATE! If you can just brush through your UG syllabus which most probably includes syllabus of GATE, then you can ace it. There are also many books penned for the preparation of GATE and sometimes you have E - Copy of these books too. You can also prepare by glancing through previous years' Question Papers and sample papers. Below I have pinned the link where you can download previous years' Question Papers, sample papers and E - Books for GATE:

https://engineering.careers360.com/articles/what-are-best-books-for-gate-preparation

Hope this is helpful!

All the best!