Melocactus azureus Cactus They are probably E

They are probably E

Sansevieria kirkii 'Silver Blue'  A very attractive upright Snake Plant or Mother in Law Tongue with thick silvery blue green leaves

Ceropegia stapeliiformis  This species has thick green to brown stems

They tend to be green when growing and pink when dormant

Melocactus azureus Cactus They are probably EMelocactus azureus Family: Cactaceae. This is a nice cephallium forming cactus with blue to blue green skin. It looks and grows like a normal cactus for several years but once it gets big enough the main plant stops growing but produces a large hairy inflorescence that continues to grow for the rest of the life of the plant. Eventually the inflorescence can be taller than the plant itself. This is more tropical than most cacti so it doesn't like cold