Perspective mockups could be created without leaving Sketch app. Magic Mirror adds the functionality of perspective transformation to Sketch artboards. So users can create high-fidelity mockups in perspective. Paid monthly subscription support up to 4x image quality and symbols.
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Combining UI design, prototyping, and feedback in one web-based tool, Figma is more than a design app. Users can iterate prototypes in collaboration, and provide feedbacks simultaneously. It is catching up with Sketch for the need in large-scale design projects. Figma is free to try with limited projects with paid upgrade per user.
Blobmaker help you to create random blobs in SVG to catch with design trend.