I'm not sure what kind this little guy is (maybe a mini barrel?):
Below is a very interesting "fairy castle" cacti with all kinds of off-shoots, and the Rhipsalis is in the foreground.
I'm quite sure the plant on the bottom right is a Echinopsis. The one towards the center in the blue pot is a Opuntia. I am thinking the one with the yellow spines looks like a small Parodia Mammulosa. No matter what they are called, they are beautiful!
This tall guy is one I bought from Mark at Creekside farm this summer. It is about 1.5-2 feet tall. Maybe a Pilosocerus with that new blue growth and hairy covering?