One zip with everything a website or web app needs: favicon.ico (16, 32 and 48 px), PNG favicons, the Apple home-screen icon, Android icons (including a "maskable" one that survives round and squircle masks), a 1024 px logo, site.webmanifest and the HTML to paste into your page.
Paste this inside <head>:
Favicons, app icons and logos from letters, emoji or your picture