Not homeopathic, but there are lots of herbal tinctures out there. The most popular is probably "Placenta Out".
Do you have concerns about delivering the placenta?
Pulsatilla possibly?
I've heard that taking a tiny bit of raw placenta and sticking it too the inside of your bottom lip can help with PPH.
You can still have bad reactions and side effects with a herbal or tincture remedy.
My placenta took just over an hour to come out with my last baby. The midwife was starting to panic a bit and said she really wanted to use the injection once it got to the hour mark. It took bloody ages and wasn't nice at all. I had to push more to get the placenta out than I did my baby! He was out in less than two minutes!
Id definitely have a physiological third stage again but may drink a ton load of raspberry leaf tea whilst in labour to help it along.