Pttrns is a great place to kickstart your UI research. Similar user interface patterns and functions are posted across different apps.
Explore related resources
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.