In Trip Wire Magazine they have made a spectacular compilation of 50+ free high-quality icon and button sets that we can download by clicking on each of the images of the original article, which I leave linked at the end of the post.
Buttons and icons are very important elements within the web design, since they are the ones that graphically show users where they should click or what they should do according to what they want to do one action or another or according to what they want the web to do for them.
Source | Over 50 free high-quality button and icon sets
Excellent! very good quality! THANKS!