avocode - Centralize design collaboration, version control, prototyping, feedback, and developer hand-off with Avocode. Work on any design, anywhere, with anyone. Sign up free 👉 https://avocode.com/.
Visily - The easiest and most powerful wireframe software for agile teams.
Zeplin - Collaboration app for UI designers & frontend developers
Handoff by Marvel - Automatically turn designs into assets, specs and code
Framer - 🔥 Design real websites right on the canvas.
Figma - Team-based interface design, Figma lets you collaborate on designs in real time.