Font Awesome contains a big bunch of great icons. They are licensed under CC BY 4.0 (see https://fontawesome.com/license/free) and you can even download them as SVG file. Just have look at https://fontawesome.com/icons/
This here is a simple tool that allows to select a font-awesome icon, change the size and the color and then take a screenshot of it to reuse it. If you do so, please check the CC BY 4.0 license at first and give credits to font awesome.
To show the icon you want, just follow 3 simple steps:
1. Go To https://fontawesome.com/icons and search for your icon.
2. Enter the data below.
3. Make a screenshot to use the icon
<i class="fas fa-user-check fa-5x" id="icon"></i>
Another option is to download the SVG file from the font awesome website, open it in an editor and change:
<path fill=”currentColor” …> to <path fill=”blue” …>