How about a Crassula like pellucida? Your observation about the leaves made me take a closer look and ponder other possibilities. It looks nothing at all like a Kalanchoe to me, but the very fine toothing on the leaf edges reminds me of some trailing Crassulas. Either way, allowing it to go a bit dry between waterings still holds. And yes, more light is in order for any of those plants. With more light it might begin to look like something we actually recognize!