Do not put anything too thick on the cut, as it can retard regrowth of the bark over the cut scar. We used to use clear laquer spray paint (when I was a landscaper) , as the wood can protect itself within a few weeks or months after the cut. Also, remember on some trees that rot easily, you may want to insure that the cut can drain well by cutting a vertical slot in the cut. When the middle of a cut branch begins to rot, water pools in it accelerating the rot, which can extend into the tree trunk. Note that this still can happen underneath a tar - covered cut scar.
THat's what our arborist buddy told us to use when I did it for a living, just cover it up with something that will last a month or so (clear spray paint - the 99 cent stuff) and make sure the cut is made in such a way that it won't hold water. i.e. If the cut faces upward, make a vertical slot with the chainsaw so water can run out, or we used a 3/4 inch auger bit to drill a hole vertically (in Live oaks that were already center rotted and filling with water)
I had a huge limb fall during a windstorm about 4 years ago. I Googled this question and found a lot of sources saying that spray is just something the "pros" use because of aesthetics....their customers expect it and feel good about "medicine" put on the wound. But, the consensus was that the tree knows how to heal itself and will do a better job of healing with absolutely nothing sprayed on. One thing is important and that is the way limbs are cut. Undercut so as to not strip too much on the bottom of the wound. Make sure the cut will drain water off and not create a rotting water catch.