I would say that most of us here are fighting the sweet and citrus flavors of sorghum. Most of the sorghum beers on the market are so sweet they are nasty.
I use as much brown rice syrup or dry rice malt (rice solids) that I can get my hands on.
As for darker, I've tried a number of things: black strap molasses, darker colored honey, coffee, chocolate, tea, toasting my own grains, blackberries, you name!
My wife has celiac, which is why I do this. I have some fruit beer recipes that turn out okay. And I made a summer ale that was pretty good but it has not aged well. I find doing this to be challenging and that is somewhat fun. But about 1 in 4 of the beers I make for her turn out okay. Most of the rest stink. The only contaminated beer I've ever made was a GF beer. I know it was a chance occurrence but it still has me down on GF beer making. And the last couple I've made have been nothing but headaches mostly because she complained about the mess.
I wish you the best of luck in coming up with some ingredients that are easy to use. I have probably made my last GF beer until I get something that is more reliable.