Here are the books of GATE ECE you can prefer given below.

Engineering Mathematics-  Dr. BS Grewal

General Aptitude- R. S. Agarwal

Network Theory- A.Chakraborty

Electronic Devices- Jacob Millman & Christos C. Halkias

Analog Circuits- Donald A Neaman

Digital Circuits-  Ronald J. Toccii

System & Signal- Alan V. Oppenheim

Control System- Benjamin C Kuo

Communications- Simon Haykin

Electro-Magnetics- Matthew N.O. Sadiku

MCQ books- Gate ECE by R.K Kanodia

For further to know about the detail you can go through with given below link.

GATE ECE books

Good Luck!

You can follow below books for preparation

Communication Modern Digital and Analog Communications by B. P. Lathi

Signals and Systems Signals and Systems by Alan V. Oppenheim, Allan S. Willsky, S. Hamid Nawab.

Electronic Devices  Semiconductor Physics and Devices by Donald Neamen.

Electromagnetic Theory  Principles of Electromagnetics by Matthew N. O. Sadiku.

Control systems: Control Systems Engineering  M Gopal, I. J. Nagrath and Automatic Control Systems  Benjamin C Kuo

Digital electronics: Digital Design  M. Morris Mano, Modern Digital electronics  R P Jain, Microprocessor Architecture, Programming and Applications with 8085  Ramesh Gaonkar

Analog circuits: Microelectronic Circuits: Theory and Applications -Adel S. Sedra, Kenneth Carless Smith and Op. Amps & Linear Integrated Circuit  Gayakwad

Engineering mathematics: Higher Engineering Mathematics  B. S. Grewal and GATE engineering mathematics  R.K. Kanodia for practice purpose.

Network Theory: Engineering Circuit Analysis -William H. Hayt and Network Analysis  M. E. Van Valkenburg