[3rd Party 18V Compatible tools - Anything other than Black & Decker Firestorm?]

Thought I'd bump this question back to the top.  As an owner of 5 different Dewalt 18V tools, I really don't want to abandon that platform, nor do I want to add another such as the 20V.  While it does seem that the older B&D 18V tools would work with my Dewalt 18V batteries, I never find any of those around for sale, used or new.

[3rd Party 18V Compatible tools - Anything other than Black & Decker Firestorm?]

I'm pretty well committed to the 18V DeWalt tools, owning 5 of them and two batteries, so no interest in moving to another manufacturer or even the 20V Dewalt line.  However, I would like to add a cordless hedge trimmer to my arsenal, and DeWalt doesn't offer that.    Doing some research, I've discovered that the older 18V Black & Decker Firestorm line used the same type of batteries (HP932K-2 or PS145), but when that brand went to the slide-in battery style ahead of DeWalt, support for the old style tools disappeared overnight.  So far, searching for a used trimer in that form factor has been futile.

Just wondering if any other company/brand uses/used the same type of battery.  I think the Porter-Cable acquisition came later and so there was never a sharing of battery footprint with that brand until the slide-in battery style.  Note, I'm assuming that B&D and Porter-Cable currently share the 18V battery footprint.

Any insight appreciated.