There is no such specific preparation material for COMEDK as NCERTs would be enough for the same and once you are done with these you can go through the below reference books as well -

HC Verma for Physics

JD Lee Concise Inorganic Chemistry

RD Sharma Objective Mathematics

And lastly COMEDK UGET Previous Year Question Paper Books should be followed for revision purpose to check the complete exam pattern, weightage and difficulty level of the questions.

Good Luck!!!