More favourite tropes:

• Generally incompetent character revealed to be incredibly skilled at one very specific thing
  
• Supernatural entity that clearly has no need for money inexplicably owns and operates some sort of relatively mundane business
  
• Device or magic spell with narrow and impractical function coincidentally turns out to be exactly what’s needed
• Terrifying monster actually wants something totally innocuous
  
• Hilariously half-assed impersonation or disguise succeeds through inattention of intended victim
• World-shaking threat averted via booze