Final answer:
Egg yolks contain three types of proteins: ovalbumin, conalbumin, and livetin.
Step-by-step explanation:
The three types of proteins found in egg yolks are ovalbumin, conalbumin, and livetin. Ovalbumin is the most abundant protein in egg whites and is responsible for giving them their thick and viscous texture. Conalbumin is a protein that binds to metal ions like iron and copper, while livetin is a minor protein found in eggs that is involved in lipid metabolism.