Since I wrote the above this morning, I have been bringing my knowledge up to date on this subject.
It appears that MalwareBytes has developed an anti-ransomware module for their A/V program, beginning last year as Beta versions in stand-alone software. It is now incorporated into their (paid) software, which is available here:
https://www.malwarebytes.com/
I have followed all the Beta releases on their forums since this morning, and it appears that this new addition to their product will pro-actively prevent both known and unknown ransomware infections. I cannot attest to its effectiveness from personal experience, but it does look to be the goods!
In my personal opinion, if I were to buy A/V s/w, this is the one product I would recommend, and have for years now.
It would certainly seem to be worth paying for their licensed product for this feature alone IMO. Even if it were not 100% effective, it seems to tackle all the common ransomware exploits head on.
I hope that this helps someone.