Please tell me what this is.
identification of cactus or succulent
That's going to be a hard one to identify because the plants are so small. Not a cactus. Could be Kalanchoe or related. Any info might help.
Looks like Kalanchoe marmorata but it hard to tell from your photo.
It could also be Kalanchoe mortagei or Kalanchoe gastonis-bonnieri.
Wait until they get a bit bigger and it will be easier to tell.