Yes. They work fine. Just don't use them for charging. Charge all batteries in the original charger they were designed for.
I know that my dad had some from Dewalt 20 volt to same for several other brands that he likes,and I have utilized. Not sure if from the same company. I believe you can 3d print some on thingiverse.com from what i recall as well, and use a parts list supplied for the wiring.
Note: Dewalt 20 volts have no over discharge protection built into their BMS so be aware of that if using a 3d printed adapter.
These make tools run, but they're dangerous because they break the safety battery safety features which are built into the tool. With the exceptions of Ryobi and Makita, most power tool battery safety features are built in to the tools, and they communicate to the battery. At minimum, they check a thermistor. More sophisticated schemes can query the battery for shutoff voltage and maximum current.