Apple - Add ‘Good News' voice to "Say" commands

Voices can be downloaded from:

System Preferences... → Accessibility → Speech

Select the System Voice and click Customize...

There You can search for Good or Bad. Voices will be downloaded and will be available in say command as well. I've tested this a moment ago.

Both of the other answers here refer users to System Preferences > Accessibility and, while there, to either Speech or Voice in the lefthand pane.

However, it is entirely possible you won't have these options. If this is the case, you can download voices instead via the following process:

1. Go to System Preferences > Accessibility
2. Select Voiceover in the lefthand pane
3. Now on the righthand side, click on the Open VoiceOver Utility... button
4. After the Voiceover Utility opens, select the Speech option in the lefthand pane
5. On the righthand side you'll now see a drop-down menu under the Voices heading
6. From this menu select Customize...
7. Now you'll see a window from which you can select voices to download
8. Select the voice(s) you want to download
9. Click OK
10. The voice(s) you selected will begin downloading. Once they're downloaded you will see them appear in the drop-down menu under the Voices heading.

A quicker option

Another process you can follow to download voices is as follows:

1. Go to System Preferences > Dictation & Speech
2. Select the Text to Speech tab
3. From the System Voice drop-down menu select Customize...
4. Now you'll see a window from which you can select voices to download
5. Select the voice(s) you want to download
6. Click OK
7. The voice(s) you selected will begin downloading. Once they're downloaded you will see them appear in the System Voice drop-down menu

AFAIK, Apple removed the Novelty sounds. They need to be downloaded manually through System Preferences > Accessibility > select Voice on the left side > System Voice menu > select Customize > select (required voice).

To know more about the voices available on the latest version of macOS. Use the following command.

say -v ?

It will list the available voices on the current macOS, which are as follows on macOS 10.12

Alex                en_US    # Most people recognize me by my voice.
Alice               it_IT    # Salve, mi chiamo Alice e sono una voce italiana.
Alva                sv_SE    # Hej, jag heter Alva. Jag är en svensk röst.
Amelie              fr_CA    # Bonjour, je m’appelle Amelie. Je suis une voix canadienne.
Anna                de_DE    # Hallo, ich heiße Anna und ich bin eine deutsche Stimme.
Carmit              he_IL    # שלום. קוראים לי כרמית, ואני קול בשפה העברית.
Damayanti           id_ID    # Halo, nama saya Damayanti. Saya berbahasa Indonesia.
Daniel              en_GB    # Hello, my name is Daniel. I am a British-English voice.
Diego               es_AR    # Hola, me llamo Diego y soy una voz española.
Ellen               nl_BE    # Hallo, mijn naam is Ellen. Ik ben een Belgische stem.
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
Ioana               ro_RO    # Bună, mă cheamă Ioana . Sunt o voce românească.
Joana               pt_PT    # Olá, chamo-me Joana e dou voz ao português falado em Portugal.
Jorge               es_ES    # Hola, me llamo Jorge y soy una voz española.
Juan                es_MX    # Hola, me llamo Juan y soy una voz mexicana.
Kanya               th_TH    # สวัสดีค่ะ ดิฉันชื่อKanya
Karen               en_AU    # Hello, my name is Karen. I am an Australian-English voice.
Kyoko               ja_JP    # こんにちは、私の名前はKyokoです。日本語の音声をお届けします。
Laura               sk_SK    # Ahoj. Volám sa Laura . Som hlas v slovenskom jazyku.
Lekha               hi_IN    # नमस्कार, मेरा नाम लेखा है.Lekha मै हिंदी मे बोलने वाली आवाज़ हूँ.
Luca                it_IT    # Salve, mi chiamo Luca e sono una voce italiana.
Luciana             pt_BR    # Olá, o meu nome é Luciana e a minha voz corresponde ao português que é falado no Brasil
Maged               ar_SA    # مرحبًا اسمي Maged. أنا عربي من السعودية.
Mariska             hu_HU    # Üdvözlöm! Mariska vagyok. Én vagyok a magyar hang.
Mei-Jia             zh_TW    # 您好，我叫美佳。我說國語。
Melina              el_GR    # Γεια σας, ονομάζομαι Melina. Είμαι μια ελληνική φωνή.
Milena              ru_RU    # Здравствуйте, меня зовут Milena. Я – русский голос системы.
Moira               en_IE    # Hello, my name is Moira. I am an Irish-English voice.
Monica              es_ES    # Hola, me llamo Monica y soy una voz española.
Nora                nb_NO    # Hei, jeg heter Nora. Jeg er en norsk stemme.
Paulina             es_MX    # Hola, me llamo Paulina y soy una voz mexicana.
Samantha            en_US    # Hello, my name is Samantha. I am an American-English voice.
Sara                da_DK    # Hej, jeg hedder Sara. Jeg er en dansk stemme.
Satu                fi_FI    # Hei, minun nimeni on Satu. Olen suomalainen ääni.
Sin-ji              zh_HK    # 您好，我叫 Sin-ji。我講廣東話。
Tessa               en_ZA    # Hello, my name is Tessa. I am a South African-English voice.
Thomas              fr_FR    # Bonjour, je m’appelle Thomas. Je suis une voix française.
Ting-Ting           zh_CN    # 您好，我叫Ting-Ting。我讲中文普通话。
Veena               en_IN    # Hello, my name is Veena. I am an Indian-English voice.
Victoria            en_US    # Isn't it nice to have a computer that will talk to you?
Xander              nl_NL    # Hallo, mijn naam is Xander. Ik ben een Nederlandse stem.
Yelda               tr_TR    # Merhaba, benim adım Yelda. Ben Türkçe bir sesim.
Yuna                ko_KR    # 안녕하세요. 제 이름은 Yuna입니다. 저는 한국어 음성입니다.
Yuri                ru_RU    # Здравствуйте, меня зовут Yuri. Я – русский голос системы.
Zosia               pl_PL    # Witaj. Mam na imię Zosia, jestem głosem kobiecym dla języka polskiego.
Zuzana              cs_CZ    # Dobrý den, jmenuji se Zuzana. Jsem český hlas.