There are several cat breeds that are known for being friendly and affectionate. However, its important to remember that cats are individuals and their personalities can vary widely, regardless of breed. Here are some of the friendliest cat breeds according to various sources:

1. Maine Coon: This breed is often described as "the dog of the cat world" due to its friendly and affectionate nature. They are great for families, including those with small children, and enjoy spending time with their humans.

2. Persian: This breed is known for being sociable and can be very loving. They enjoy snuggling up with their favorite human and have a laid-back and relaxed nature.

3. Ragdoll: This breed is often described as the friendliest breed of cat. They are laid back and cuddly, making them the perfect companion cat.

4. Siamese: This breed is known for being very vocal and communicative with their humans. They are often described as the quintessential "peoples cat" and love to be in their humans lap or bed.

5. Sphynx: This breed is often described as the social butterfly of the cat world. They are very affectionate and love to be around their humans.

6. Burmese: This breed is super-affectionate and loves curling up on the sofa with their favorite human. They are laid back and make great companions.

7. Abyssinian: This breed is often described as the "You Only Live Once" cat due to their energetic and playful nature. They are also very friendly and love to interact with people.

Its important to note that breed is not the only factor that determines a cats personality. Many cats in need of homes are a mix of breeds, and a cute pair of tufted ears or a soft stripey coat could reveal a friendly and affectionate cat regardless of breed.