They've been with me for 15 years. Don't know their names because picked them up after neighbors moved out. Incredibly sturdy. During 6 weeks of absence I didn't want to use any 120V watering devices plugged in, and braced myself to find my green friends dead in the apartment, but they survived. Next time will try watering with clay cones, but in case that they die during a very long absence, would like to know their names, in order to replace them - or how to take care of them so that they would survive. One looks like Agave, about 5" tall, propagates with offsets. It doesn't look well on the photo, and might not recover after the drought. Another one is a climber, blossoms once a year with clusters of tiny white flowers, dripping nectar sweet as candy - I don't think there is anything that can kill this one.
Yep. What Junglekeeper said. (For the record, the Sansevieria doesn't look like the usual Sansevieria trifasciata, but it still is; it's just a cultivar that has short leaves instead of long ones called Sansevieria trifasciata 'Hahnii.')
Thanks! I suspected it to be one of Sansevieria but couldn't find the exact match on the web. Wax Plant - this name makes sense too. Its nectar is dense like a wax.