Is there a surgery that can take fat from stomach and add to butt?

Yes. Some plastic surgeons will take fat from the abdomen, process it while you are asleep and then implant it into the buttocks area. It is expensive and not all plastic surgeons do it.
Fat transplant. Liposuction can remove fat from an area, and then it can be processed for injection into another area. The fat is normally transferred into the areas on the face, large volume ft transfer is not commonly done.There is possibility of an uneven appearance even of fat survives which is decreased with large volume fat transplant.See experienced plastic surgeon or dermatologist.
I wouldn't recommend. While fat grafting increases in popularity all the time, it is still rather unpredictable in terms of result and longevity. I am not aware of any successful use of fat grafting in an area exposed to pressure, like the buttocks.
Brazilians "do it" Yes. This is called the brazilian butt lift and this is commonly performed as a method of buttock enhancement. It is a combination of strategic liposuction of the lower back and hips with selective injection to the buttocks.
Of course. This is one of the most common procedures i perform. If you are a suitable candidate and you have enough fat, we gently remove the fat to avoid damaging it in any way. I prefer to suction it manually without any machine. Then after careful preparation the fat is placed into the buttocks, sculpting the area to achieve the result you need. It is often accompanied by a tummy tuck, but not always.
Fat transfer. Is standard suction-assisted lipectomy(liposuction), but with use of the otherwise discarded fat by cleaning it and reinjecting the living material-which contains stem cells wherever the pt wishes. Special harvesting devices are used. We provide free info @ 877drsisto.
Yes. Large volume transfer of fat from thighs/abdomen areas may be grafted to buttocks to increase fullness & give some help to depressions. Most commonly syringe system fat removal + addition of platelet concentrates will enhance the "take" of the grafts to provide more consistent and quality results. Fat grafting has currently exceeded the use of artifical implants, as there are fewer complications.
Brazilian Butt Lift. Yes! the brazilian butt lift is a procedure which uses fat transfer techniques to create a perkier and more robust buttocks. The result is a totally transformed upper body as you have a sculpted torso with a prominent buttocks. . To perform the procedure, we first remove fat via liposuction, process the fat, and then reinject just the best fat cells into the buttocks. Patients love it!