The best alternatives to Wireframe Designer are Root UI Kit, Karma Wireframe Kit, and MockFlow. If these 3 options don't work for you, we've listed a few more alternatives below.
What do you think of Wireframe Designer?
Blaze— Create beautiful 1-click content in your brand style with AI
Root is a carefully minded set of Sketch & Figma files containing UI components and wireframes synced with a minimal weight style guide. A tool to help both designers and developers get a project started, create prototypes, or build a design system upon it.
Karma is a carefully-crafted wireframe kit with 900+ unique blocks and pre-built components. Karma is a wireframe kit made for Figma users. It’s based on the most advanced aspects of Figma with centralized and shareable design consistency.