Cactus complete desert landscape

Since arriving in Arizona in January, I've been intrigued with the variety of cacti growing here, from kitchen window sills to gardens to deserts,

An estimated 1,500 to 1,800 cacti grow around the world. Here are pictures of some I've found growing in Arizona. Unfortunately, I can't identify any of them. Well, I could I guess if I were willing to go through thousands of online photos or knew the official Latin name. So I just enjoy looking at the cactus  and preserving them in my photobook of memories.

If anyone can identify any of the cactus above, please leave a comment. Thanks!