Hello aspirant, hope you are doing good.

So, first thing you need to know is that preparatory rank isn't a real rank for bagging a seat in IIT, it is a rank to get into preparatory courses. This means, under this rank, the category students are given an opportunity to be taught the preparatory courses for a year,in some of the IITs, and there will be an exam at the end of the year. If you qualify for the exam, only then will you be able to secure your seat in the IIT.

If you want to know about all the possible colleges you can get into with your JEE Advance rank, you can get it here:

https://engineering.careers360.com/jee-advanced-college-predictor?icn=QnA&ici=qna_answer

Hope this helps you. Good Luck!!