Hard to discern any details (even in the enlarged view) of the one on the left, other than it being a cactus.
Middle one is a Stapelia, possibly S. gigantea, but you'll need bloom to confirm.
Right side is Haworthia attenuata.

If you take another pic of the cactus by itself, we can take another crack at it! :)

Thanks a bunch rosemariero, here is another close-up of the the cactus.

Here is a link that might be useful: {{gwi:373114}}

Thanks for the additional pic. Still hard to say, but perhaps a Notocactus, like N. uebelmannianus.