Visily - The easiest and most powerful wireframe software for agile teams.
Zeplin - Collaboration app for UI designers & frontend developers
PSD to Sketch Design Converter - Convert a Photoshop design to a layered Sketch file for free
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/.
Sympli - Design handoff & collaboration for Figma, Adobe XD, Sketch, and Adobe Photoshop. Design Verison control for Sketch.
Bootsketch - Ship products instead of renaming layer groups