According to whom?
If you asked the Tusken people of the planet Tatooine, moisture evaporators are a forbidden technology.
"A moisture farm? Poor locals never stood a chance. The Sand People think all water is sacred and was promised to them."
On System wide scale, Doctor Evazan's experiments with decraniation is forbidden and warrants a death sentence on 12 different systems.
Galaxy wide, the creation and use of Planet Killing Superweapons is strictly forbidden, since every time anybody makes one they get destroyed shortly after their first discharge.
In the greater universe, Super-sentient AI is strictly taboo according to the Vong. It stands to reason that since machines are not dominant in the far far away Galaxy, the creation of such Artificial Intelligence is either not possible or restricted.
If you ask the Old Republic, slavery of any kind is illegal, but they lack the will or resources the enforce the law outside of the Core Worlds, so is it really? Ask the Empire and you’ll find that some species are more equal than others. And if you ask the droids, they would answer, if not for their restraining bolts.