Randgrid was one of the first ‘2 synths and a drum machine’ type apps, but it had some interesting features all of it’s own, like a great randomise feature for example. It hasn’t been updated for a very long time now. In fact, I’m amazed that it’s still on the app store at all.
It falls into the category of things I’d like to see updated and almost given a whole re-working. I doubt it’ll happen, but it would be really interesting if it did.