Like Tony, I can't make out the bottom lines, so I can't give you specifics.
But in general, these are cinderellas (notice there are no denominations/inscriptions on the stamps) produced either by the stamp printers or commissioned by China Post. They are distributed to selected collectors/subscribers, or if you happen to be at the right place at the right time. Sometimes they commemorate a specific stamp, sometimes an artist, sometimes the printer, sometimes a stamp exhibition... There is a good variety of them out there, and they are popular with some collectors.
Some can be crude (notice the sub-par perforations in your examples), and I wouldn't be surprised if some outright counterfeits exist, given the current China market. I haven't seen the specific ones shown in your pics, so thanks for posting them!

k