Whimsical Wireframes - Lightning fast wireframing with real-time collaboration.
Source Wireframe Kit - Library of 537 blocks for desktop and mobile prototyping
Figma Map Maker - Figma plugin to generate map, supporting Google Maps, Mapbox
Form Wireframe Kit by InVision - A free wireframe kit from InVision
Figma - Team-based interface design, Figma lets you collaborate on designs in real time.
iOS Wireframing UX Kit - An easy, speedy way to wireframe for iOS