Main button icons for mods that lack them, or otherwise look out of place. Just like the other two expansion mods for Vanilla Textures Expanded, except with a few more icons, slightly better compatibility and a different style once again.
This isn't related to Vanilla Textures Expanded anyway, but that mod adds icons to vanilla buttons, and this is meant to fill the gap VTE leaves for mod icons. The preview image includes some of their icons.