The best alternatives to ReacType 3.0 are Octopus, Paper Prototype, and Visual Flows. If these 3 options don't work for you, we've listed a few more alternatives below.
Get your ideas on paper. Pre-formatted iPhone templates make it easy to quickly test out ideas before going to Sketch. They're sticky so you can move them around on a whiteboard and visualize the user flow.
You don’t have to be a research expert to understand your users. Learn how people use your SaaS products with the first user research tool built for UX Designers.