Now UI Kit - A beautiful Bootstrap 4 UI kit. Yours free.
Design Resources - A curated list of tools in one place to help designers
Get Shit Done - Free Bootstrap 3 UI kit
WebCurate.co - 1600+ Useful Tools. All Hand-Picked. All in One Place.
Dashboard UI Kit - A modern & responsive dashboard UI kit for designers.
UI HUT - 12,000+ exclusive design resources for Figma, Sketch & XD