IANAL, but synth patches are usually royalty-free, meaning that you can use them without further cost for whatever you like. As long as you are not going to sample a synth's whole preset bank and try to sell it (or put it in a module, for that matter), you can't really get into trouble for it. If this was a problem, you would have to avoid any kind of one-shot solo sounds in your musical productions, because someone could sample them from your music. You will also certainly not get into legal trouble for making your sounds or using 3rd party sounds with such a synthesizer and then spreading them in modules. Synths are made to be heard, after all. I doubt that Roland would for example sue me for creating modules with samples from the D-50, especially since many of my samples are actually from 3rd party banks and not the factory presets. Still, I write "D-50" in my sample credits because I can't be bothered to look up from which exact bank I took which exact sound. Plus, a synth preset is usually more than just a simple one-shot sample - they are also made up from expression, like volume / aftertouch changes and the like.
