It depends on what you call "design". User flow, interactions, states, rectangles and colors or just rectangles and colors. If first, there are a lot of other tools, maybe not so hyped so you don't see them every day. Just to name a few: Axure, Justinmind, iRise, Indigo Design. Recent version of Adobe XD is quite a powerful tool as well. With the rise of rapid application development tools we possibly can add Bubble, Retool, Outsystems and similar tools to this list too.