Cartoons are alphabetized by tags, with a few tags still to do, and many cartoons still to be uploaded. Of course, you can still use the search box, but I thought this might be fun if you are looking for certain topics.
All cartoons are for personal enjoyment only, and are not to be reproduced in any way without specific permission. Using cartoons without permission is illegal and is subject to fines up to $150,000 plus legal fees. (Fair Use does not have different laws for schools; there are 4 rules for Fair Use, and none of them would include a student or teacher using a cartoon for any reason.)
This page explains how to buy cartoons.