What Comes After "Z?"

I woke up with this burning question, "What letter comes after the letter z?" to which I reply:

1. "Y" if you're listing the letters of the alphabet in reverse alphabetical order.
2. "A" if you're listing the letters of the alphabet in alphabetical order in sequence.
3. "S" if you're spelling the name Zsa Zsa.
4. "B" if you're spelling the name Zbigniew Brzezinski.
5. "O" if you're spelling the word zoo (on and on for zebra, zylophone, zipper, etc).
6. "N" if you're looking at a random rack of Scrabble letters.
7. "%" if you're inventing a 27th letter of the alphabet.
8. "Z" if you're into singers with long (long!) white beards.

Now, back to work.......