square-chevron-down from coolicons in Line with regular corners. expand, dropdown, open, more, select, caret, box. Other styles and corners: @coolicons/<style>/<radius>/square-chevron-down with line, duocolor, duotone, fill or bulk and sharp or round. Leave out regular, like @coolicons/fill/square-chevron-down, and use @coolicons/square-chevron-down for line with regular corners.
pnpm dlx shadcn@latest add "https://coolicons.cool/r/square-chevron-down.json"