Clickbank can provide you with an opportunity to earn from multiple products that they have. You can endorse as many products as you like in their marketplace. In this manner you get to have the opportunity to make earnings from all the products that you endorse. Provided of course you work things out.
The best part about this is that you have an unlimited opportunity to earn as much as you like. It is important however that you establish a traffic generating site or any online method that converts into sale, because clickbank is all about selling. You will not earn anything unless you make a sale by way of people buying products through your link.