The snake plant has what is called CAM photosynthesis (crassulacean acid metabolism) which is why it is said that it produces oxygen at night. It's not the only plant that does CAM but it's a common houseplant. Here's the Wikipedia page on CAM photosynthesis:
https://en.m.wikipedia.org/wik...
Having said that, I'm not at all sure that they really do release significant amounts of oxygen at night.
