I like to see new icon ideas, and I think you did a good job making logical legends out of a single repeated triangle, but I’m not sure I like the result that much. I think maybe using only that small triangle is a bit too much repetition? I do like the lowercase alphas.
I like the colors and I think you got the green right for algae, but I don’t think I would put it on my own keyboard. I’m just not a fan of that green, or really the idea of algae on my keyboard-lol.
It would definitely be worth trying more red in the brown.
Also, I don’t know how new you are, but recently most proposed DSA sets have been switched to KAT or KAM. I think the profile is similar but offers some advantages over DSA. I actually don’t know the specifics, but just thought I’d mention it in case you hadn’t considered it.