There's in-betweens; '1T SRAM' or eDRAM.

Of course, 1T SRAM isn't really SRAM, but my understanding is it doesn't require external refresh like eDRAM, is a bit easier to fab on-die than eDRAM, and is half the mm2 per Megabit compared to real SRAM (15% more die size than eDRAM)...