HitmanPro.Alert may not fit the formal definition of a BB, but it sure does a good job, and it is signatureless
I agreeAvast Free has ID Protection from AVG. A custom installation may allow you to install the Behaviour Shield without File System Shield. Otherwise SONAR in Norton, but you won't be able to custom install.
I tested ID Protection before AVG integrated it into their Antivirus many years ago, it's one feature that I liked the most. It's now included with Avast Free.
I agree, some of the warnings are cryptic for a casual user, but I'm used to it and no problem.I've tested Emsisoft, but it's too complex for casual users when it shows the warning imo.