checkbox from coolicons in Line with regular corners. unchecked, empty, select, option, box, task. Other styles and corners: @coolicons/<style>/<radius>/checkbox with line, duocolor, duotone, fill or bulk and sharp or round. Leave out regular, like @coolicons/fill/checkbox, and use @coolicons/checkbox for line with regular corners.
pnpm dlx shadcn@latest add "https://coolicons.cool/r/checkbox.json"