I wound up using the Lookout Ad Network Detector app and have had zero problems. I don't know if it helps that I'm using Lookout in general for virus protection etc, but have had no problems with any unwanted push notifications since installing it. I did end up removing one or two apps (can't remember which ones right now) but even ones that it says are problematic haven't been. Definitely recommended.
Huge thanks to PossumPete and o2bnclemson. I downloaded your suggested apps and have now detected all of my apps that were creating push notifications. Agree that some of them were very risque and glad to be rid of them.