100 Daily UI Challenge is a free library of products, elements, and screens made by Jan Janeczek.
Free Figma Resources
A free collection of iOS 13 core components and selected screens in dark and light versions for Sketch and Figma.
Free Pixel 4 phone and Pixelbook Go laptop mockups in Sketch, Figma, and Photoshop file formats.
Comida is a free UI kit for Sketch and Figma that you can use to get started with a food delivery app design.
Mobile Apps Library is a free UI kit including 120+ screens from 4 popular social apps: WhatsApp, Messenger, Instagram and Telegram.
Free collection of the best free iPhone 11 mockups in many different file formats (Sketch, PSD, Figma, Ai) to showcase app designs.
Free sample pack from Fragments for Android, a wireframe kit for Sketch, Figma and Adobe XD, which includes 20 free layouts in the “Reader” category.
Fragments is a wireframe iOS kit for Sketch released by Pixsellz that you can use to build any kind of mobile app.
Ticketapp is a free event booking app design concept released by Check JCD that includes 12 ready-made screens.
Paaatterns is a nice collection of free handcrafted patterns rincluding 22 beautiful and colored design motifs made of vector shapes.