Most commonly used metatags

metatags.html

<meta name="theme-color" content="" /> <!-- put hex color -->
<meta name="description" 
    content="Veja projetos da comunidade no Github.">
<meta name="keywords" content=""> <!-- put the keywords -->
<meta name="author" content=""> <!-- put the author -->
<meta name="robots" content="index, follow">
<meta property="og:title" content=""> <!-- put a title -->
<meta property="og:description" content=""> <!-- put a description -->
<meta property="og:image" content="" class="metaimg"> <!-- put a link to an image -->
<meta property="og:image:width" content="400" />
<meta property="og:image:height" content="300" />
<meta property="og:url" content=""> <!-- site link -->
<meta name="twitter:card" content="summary_large_image">