I have been Brewing Extract Beers since 1992. I've always used some grain, though. Last year I brewed 13 five gallon batches of various Brown Ales, Scottish Ales, & Sweet Stout. I bottle all mine. I mostly use Briess plain Amber DME.
I love Crystal Malt, for the Flavor, color and mouth feel, that it adds.
I also frequently use Chocolate Malt.
Occasionally, I use Black Patent Malt or Roasted Barley, for various recipes.
I do not make many light colored Beers. But over the years,I have used Carapils once or twice. Oh, and there is Malto-dextrin powder, too.
I have recently tried Malted Barley that I have Toasted, lightly. It's interesting in the flavor & effect it adds.
I think you can make some Excellent Extract Home-Brews, with the addition, of a pound or so of various Grains, steeped in your water, as it warms up to boiling, and then Sparged.
I'm just sayin'.........
Works for me.