While some of these methods may be controversial, none of them have been undeniably proven to be dangerous, and many women have had success with them. My doctor recommended many of these, including castor oil and nipple stimulation (which I tried several times with 0 adverse effects). That being said, I wouldn’t try most of these without doing your own research and getting an opinion/approval from your care provider, since it is controversial. Can’t really lose anything by simply waiting, though! Baby isn’t gonna come until they’re ready.
This list is pretty minimalistic, though. Could share a bit more info...