Actors:
* Arnold Schwarzenegger (actor, politician)
* Al Pacino (actor)
* Anne Rice (author, screenwriter)
* Alan Rickman (actor)
* Adrian Brody (actor)
* Anthony Hopkins (actor)
* Anya Taylor-Joy (actress)
* Aaron Paul (actor)
* Alfred Molina (actor)
* Archie Panjabi (actress)
Musicians:
* A.R. Rahman (music composer)
* Ariana Grande (singer)
* Avril Lavigne (singer)
* A$AP Rocky (rapper)
Authors:
* Arthur Conan Doyle (author)
* Agatha Christie (author)
* Ayn Rand (author)
* Alice Walker (author)
* Amy Tan (author)
Politicians:
* Andrew Roberts (historian, author)
* Al Gore (former Vice President of the United States)
* Ariel Sharon (former Prime Minister of Israel)
Others:
* Andy Warhol (artist)
* Albert Einstein (physicist)
* Alexander Graham Bell (inventor)
* Audrey Hepburn (actress)
* Anna Wintour (editor)
This is not an exhaustive list, but it provides a good starting point for famous people with the initials "AR". You can search online for more specific lists by profession, nationality, or other criteria.