https://ss64.com/osx/say.html

say --voice='?' | grep "en[_-]"
Agnes               en_US    # Isn't it nice to have a computer that will talk to you?
Albert              en_US    #  I have a frog in my throat. No, I mean a real frog!
Alex                en_US    # Most people recognize me by my voice.
Allison             en_US    # Hello, my name is Allison. I am an American-English voice.
Bad News            en_US    # The light you see at the end of the tunnel is the headlamp of a fast approaching train.
Bahh                en_US    # Do not pull the wool over my eyes.
Bells               en_US    # Time flies when you are having fun.
Boing               en_US    # Spring has sprung, fall has fell, winter's here and it's colder than usual.
Bruce               en_US    # I sure like being inside this fancy computer
Bubbles             en_US    # Pull the plug! I'm drowning!
Cellos              en_US    # Doo da doo da dum dee dee doodly doo dum dum dum doo da doo da doo da doo da doo da doo da doo
Daniel              en_GB    # Hello, my name is Daniel. I am a British-English voice.
Deranged            en_US    # I need to go on a really long vacation.
Fiona               en-scotland # Hello, my name is Fiona. I am a Scottish-English voice.
Fred                en_US    # I sure like being inside this fancy computer
Good News           en_US    # Congratulations you just won the sweepstakes and you don't have to pay income tax again.
Hysterical          en_US    # Please stop tickling me!
Junior              en_US    # My favorite food is pizza.
Karen               en_AU    # Hello, my name is Karen. I am an Australian-English voice.
Kathy               en_US    # Isn't it nice to have a computer that will talk to you?
Moira               en_IE    # Hello, my name is Moira. I am an Irish-English voice.
Oliver              en_GB    # Hello, my name is Oliver. I am a British-English voice.
Pipe Organ          en_US    # We must rejoice in this morbid voice.
Princess            en_US    # When I grow up I'm going to be a scientist.
Ralph               en_US    # The sum of the squares of the legs of a right triangle is equal to the square of the hypotenuse.
Rishi               en_IN    # Hello, my name is Rishi. I am an Indian-English voice.
Samantha            en_US    # Hello, my name is Samantha. I am an American-English voice.
Serena              en_GB    # Hello, my name is Serena. I am a British-English voice.
Tessa               en_ZA    # Hello, my name is Tessa. I am a South African-English voice.
Tom                 en_US    # Hello, my name is Tom. I am an American-English voice.
Trinoids            en_US    # We cannot communicate with these carbon units.
Veena               en_IN    # Hello, my name is Veena. I am an Indian-English voice.
Vicki               en_US    # Isn't it nice to have a computer that will talk to you?
Victoria            en_US    # Isn't it nice to have a computer that will talk to you?
Whisper             en_US    # Pssssst, hey you, Yeah you, Who do ya think I'm talking to, the mouse?
Zarvox              en_US    # That looks like a peaceful planet.