I’d call them USB adapters; “chargers” is probably slightly more common though never sat right with me since they can be used to power things other than charging.
Or more in the past we would call any kind of power adapters “transformers” but don’t seem to hear that much any more.
Yeah, I’m sure you’re right, my comment about transformers I guess was more about colloquial usage, i.e. rightly or wrongly we called DC power supplies transformers in the 90s. I also don’t know how local that was, maybe it was just my family!