I watched three episodes of Batman: the Animated Series - Feat of Clay (a two parter about the origin of Clayface) and Joker's Favour (the first appearance of Harley Quinn).
It's kind of crazy how much Harley's changed from her original concept to modern portrayals, and seeing Clayface in these episodes made me want to see what they could do with him in a movie. (obviously, he'd be largely CGI, and he'd likely be a nightmare to make, which is likely why they haven't even tried to include him yet) Lucius Fox had a bigger role in the Clayface episodes than he did before, though he's very different from the Nolan version who is well aware that Bruce Wayne is Batman. (then again, he's part of the Board of Directors here, rather than being the guy who gives Batman his tech)
I think I'm going to play Bug Fables for a bit. I'm planning to stick to Hard Mode for now, and I'm aiming to complete the bestiary at the very least. (100% completion would be ideal, but that depends on how difficult that is)