Is the idea of permanent magnet "free energy" generators impossible?

I am wondering if permanent magnet generator devices are possible to build and make work. I know you can’t have such a thing as perpetual motion, but a magnetic generator is not really perpetual motion, at least not how I understand it.

If a magnet can push another magnet, is it not then possible to align them in such a way that you can build a generator? as I understand it, this is a mechanics and engineering problem, not a limitation by the laws of physics.

Will it ever be possible to create a magnetic “free energy” generator?

Why, why not?