And of course, if you want to grab the extension — fixthegulf.com 😉

I'm also a fan of armconverter.com/decryptedapp... , which will give you decrypted versions of apps, useful for throwing into a disassembler

ipatool is great - there's an issue affecting it + similar tools where you can only download .ipa's you've already obtained a license for via a real device ( github.com/majd/ipatool... ), but if that's not a problem for your use case it's otherwise lovely