This webtools 101 is dedicated to a collection of tools used by frontend website developer slash designer and the curious ones.
Subtle Pattern is the website that provides texture background. My favorite is gray: https://www.toptal.com/designers/subtlepatterns/page/2/?s=gray
Free vector icons (tons of royalty free content): flaticon.com
Similar yet unique collection of icons and symbols inside font: https://fontawesome.com/
For free stock photos and videos: https://unsplash.com/
Frontend CSS/JS/JSX tricks: