There isn’t an official Heardle Unlimited (like there’s a ‘Wordle Unlimited version allowing you to play multiple rounds of Wordle per day), but there is a heardlegame.co/heardle-unlimited website which isn’t actually affiliated with the original Heardle game app. However, this website does give you the option to play as many rounds of Heardle as you want, and also gives you different Heardle themes to play, like Heardle 90s, TayHeardle (Taylor Swift Heardle), Harry Styles Heardle and more.