In Scotland, it used to be heavy or light beer. The latter was probably similar to mild beer in England. IT was often darkrr in colour although pale ale was often sold as light beer too. Usually, it was slightly cheaper and not quite as strong as heavy beer but different breweries still produced a different type of beer. They were often very different.

Most good real ale pubs still sell pale ales but these will vary in strength and price. So, it's not quite the same as getting a pint of light or mild as such.

I'm not too "au fait" with all the different keg beers these days though. I prefer cask or real ale whenever I can get it.