For aptitude preparation people in India blindly trust R.S Agarwal. I agree it is a good book with detailed, questions answers, solutions and explanations.

But for GATE you need more advanced aptitude topics with previous years questions answers focused on GATE. I highly recommend to try Aptitude & Reasoning for GATE & ESE, By Hemant Jain (Author), OnlineVerdan (Contributor), Infinity Educations. This book is specially written for GATE candidates. It is the best aptitude and reasoning book for GATE.

I found this information from this link: https://www.basictell.com/blog/best-quantitative-aptitude-books-competitive-exams/

• How to Prepare for Quantitative Aptitude by Arun Sharma
• High School English Grammar by S Chand publication
• Quantitative Aptitude for All Competitive Examinations by Abhijit Guha
• A Modern Approach to Verbal & Non-Verbal Reasoning by RS Agarwal
• Rapid Quantitative Aptitude with Shortcut Tricks for Competitive Exams by Disha publication.