I have a few "Mother of Thousands" [0] which started out as a single plant that I was gifted but it grew so rapidly that I now have about 6 pots of them. They produce tiny little baby plants on the edges of each leaf which then drop off. They are also nigh on impossible to kill (I rarely water them). I used to plant all the tiny 'seedlings' but now throw them away as there are just way too many. Be aware though that they are toxic so maybe not a good mix with pets.

[0] https://en.wikipedia.org/wiki/Bryophyllum_daigremontianum