That's mostly Metabo and some niche brands, not the kind of everyday power tools.
Oh, I was hoping you were saying Ferrex was compatible with Metabo, that would be nice. It seems not though, just compatibility with the above list? (Ferrex is known for having keenly-priced spare batteries, I'm not sure about the others?)
One trouble with the cheap brands is they don't really maintain a battery platform - they're often changing the designs of things, eg Aldi often has tools which aren't on the Ferrex system.
I think TBH this is one case where having a whole-house battery increasingly makes sense. Keep basic services running, not just the router but the lighting, boiler controls, pumps, etc. No cooking or lighting, but at least basic life support.
It's not cheap to do, but compared with other care services it could be worth it.
Theo