There are many species, but here are the ones I already have:
Cleistocactus acanthurus
Cleistocactus baumannii
Cleistocactus buchtienii
Cleistocactus candelilla
Cleistocactus clavispinus
Cleistocactus ferrarii
Cleistocactus hildegardiae
Cleistocactus hyalacanthus
Cleistocactus peculiaris
Cleistocactus ritteri
Cleistocactus samaipatanus
Cleistocactus senilioides
Cleistocactus sextonianus
Cleistocactus smaragdiflorus
Cleistocactus strausii
Cleistocactus tominensis
Cleistocactus winteri
Cleistocactus winteri ssp. colademono

Any not on that list I would be interested in!

I have several cactus (segments/cuttings/pups) and other plants, as well as some seeds available for trade. Trade list changes, so email me if you have a Cleistocactus not listed above if you are interested in a trade!

Cheers,
Tristan