I recently printed the Dragon Skull from Printed Into Existence, since it is a bit tail heavy I created this simple stand.

The stand has the shape of the bottom of the skull which simply rests on it and therefore can be printed afterwards.
Since probably everyone has scaled this model differently, it is also important to adjust the stand to the size of the skull. I've printed the skull in 250% size, accordingly the stand is adapted to this size, I've added a smaller version of the stand for a skull size of 100%.

To scale the stand to another size and you have already printed the skull do the following:
Measure the distance between the two outer horns as shown in the picture. Since this is the widest part of the skull you can scale it to the measured dimension, then you can see how much % the skull was scaled to (250%= 147,41mm 100% = 58,96mm) and scale the stand accordingly.