There are 8 types of contracts discussed in the document: express contracts, executed contracts, adhesion contracts, and void and voidable contracts. Express contracts have explicit terms agreed upon by both parties. Executed contracts are ones where all terms have been fulfilled, like delivery and payment for an item. Adhesion contracts are standard forms like those from telecom companies. Void contracts are not legally binding, while voidable contracts are valid unless one party chooses to void it based on legal grounds.