Very few people use these:
- Asterisk
- Back-slash
- Colon
- Dot
- Eight
- Four
- Gene
- Hyphen
- Illicit
- Jean
- Knows
- Louder
- Minus
- Nine
- One
- Period
- Qu’orn
- Repeat
- Seven
- Three
- Underscore
- Vowels
- Won
- X-mas
- Yiddish
- Zero
(Bonus points: I dare you to come up with a more worse one.)