Characters Which Don’t Deserve to Be on My First-Level Keyboard:
` (Backtick/grave)
\ (Backslash)
; (Semi-colon)
Characters It Would Be More Useful to Have on My Keyboard, as I Refer to Them in Conversation More Frequently Than I Ever Need to Type Any of the Previous List of Characters:
Omar Little from The Wire
Captain John Joseph Yossarian from Catch-22
Martin Q. Blank from Grosse Pointe Blank
Update: After a few minutes of photo editing, I present my personally more useful keyboard: