Stack Wallet left a massive impression on me. When opening it and creating a wallet, it immediately bombards you with graphs about the current exchange rates of several crypto currencies. This sent my eyes spinning.

As a good example, I would point at ZEUS. Dead simple UI, shows just what is needed, big buttons with clear meanings. The fact that you can swipe the two bars is not said anywhere, but you might figure it out by accident (which is still bad design.) Still, Zeus' UI is pretty good.

Since most apps use Electron or other webview-based frameworks these days, sticking to WAI-ARIA is a good starting point for screen reader access - and sticking to a KISS-ish UI design helps visually impaired people. Chosing a good and distinct color scheme helps color-blind people (strong contrasts are still visible to them; change your screen to only displaying Monochrome for a very, very, very, very rough representation - its not even close to that, but can help as a guideline for the basics).