Hello,

If you have not started the preparation yet, the you may buy self stude guide:

(a) Universal's Guide to CLAT & LL.B. Entrance Examination 2019 -2020 29th Edition

(b) Arihant Self Study Guide CLAT (Common Law Admission Test) 2019 

For General knowledge as it covers a good portion of the exam, you can buy either of the two Pratiyogita Darpan or Manorma Year Book. Lucent's General Knowledge will also be a very good option for static gk.

For Genral English High School English Grammar and Composition by Wren and Martin and Word Power made easy will be sufficient

This is just an example of few of the books. 

Their would be 5 section in the paper:

GK& Current Affairs

English

Legal Apptidue

Maths

Logical reasoning

for more details about the exam pattern and books to be reffered, please visit the following link:

https://law.careers360.com/articles/clat-syllabus
https://law.careers360.com/articles/best-books-for-clat-2019