Cacti and other desert plants

I have never lived in an area where cacti were a native plant, so they were fascinating to see. Inadvertently, I think we must have been on vacation at a good time of year as so many of the varieties of cacti we saw were blooming and looking really plump and good. I have no idea what their names are, so if anyone can name any of them for me, I'd be really happy to know them. I'll just number them, so it is easy to give a name for a number without further confusion. Help please? (some have now been named)

1. Prickly Pear Cactus


2. Barrel Cactus


3. Organ Pipe Cactus


4.

5.

6. Agave?


7.

8. Saguaro Cactus





9.Teddy Bear Cholla