Related Clues:

• Desirable extra
• "Besides . . ."
• Word used when adding?
• Word used when adding
• "Wait, there's more ..."
• 'What's more ...'
• "Besides that ..."
• Furthermore...
• Exces-sively
• Adverb with "optimistic"
• "On top of that"
• It precedes an extra point?
• On top of everything else
• "Not only that . . ."
• 26-Across enhancement