Environment both: https://img.shields.io/badge/environment-both-4caf50?style=flat-square
Environment any: https://img.shields.io/badge/environment-any-707070?style=flat-square
Environment client: https://img.shields.io/badge/environment-client-1976d2?style=flat-square
Environment client, optional server https://img.shields.io/badge/environment-client%2c%20opt%20server-536a9e?style=flat-square
Environment server: https://img.shields.io/badge/environment-server-orangered?style=flat-square
Environment server, optional client https://img.shields.io/badge/environment-server%2c%20opt%20client-c65135?style=flat-square
Fabric: https://img.shields.io/badge/mod%20loader-fabric-d64541?style=flat-square
Forge: https://img.shields.io/badge/mod%20loader-forge-1976d2?style=flat-square
Fabric, external: https://img.shields.io/badge/mod%20loader-fabric-d64541?style=flat-square&logo=data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAA4AAAAOBAMAAADtZjDiAAAAElBMVEUAAAD///////////////////8+Uq06AAAABXRSTlMAgHd/wE1PadYAAAA3SURBVHheY0AGqqEBDAyhoQFMIDqAgYHRFUKLGoFpxmAGARAtasDAAKIFGVjBNANWOhQEGNABACDHCJDx1GXeAAAAAElFTkSuQmCC
Forge, external: https://img.shields.io/badge/mod%20loader-forge-1976d2?style=flat-square&logo=data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAA4AAAAOBAMAAADtZjDiAAAAElBMVEUAAAD///////////////////8+Uq06AAAABXRSTlMAgHd/wE1PadYAAAA3SURBVHheY0AGqqEBDAyhoQFMIDqAgYHRFUKLGoFpxmAGARAtasDAAKIFGVjBNANWOhQEGNABACDHCJDx1GXeAAAAAElFTkSuQmCC
Curseforge's HTML sanitisation doesn't like these URLs, so you can use the attached .svg files instead of the shields.io hosted ones - just right click one and select "View Image" to get the raw URL.
The external link icon is licensed CC0, with the following SVG source code:
<?xml version="1.0" encoding="UTF-8"?>
<svg width="14" height="14" version="1.1" viewBox="0 0 3.7042 3.7042" xmlns="http://www.w3.org/2000/svg">
<g fill="#fff">
<path transform="scale(.26458)" d="m2 2v10h10v-5h-1v4h-8v-8h4v-1z" stroke-linecap="round" stroke-linejoin="round" stroke-width="1.0016"/>
<path d="m1.5875 1.8521 0.26458 0.26458 1.0583-1.0583-0.26458-0.26458z"/>
<path d="m3.4396 0.26458v1.3229l-1.3229-1.3229z"/>
</g>
</svg>