Here's a list of mundane and combat-ineffective spells I made. Replace a few of these on a wizard's spell list when the party catches them off guard. Also good to slip these in found spell-books for a few laughs.
Level 1 Spells/Cantrip-ish spells
Makes a bed so nice you could bounce a silver piece off of it. In combat: pretty useless, but in rooms covered in sheets and pillows it can act as Entangle. Perfect for when the prostitute turns out to be an assassin.
Mersault's Salivating Seasoning
Enchantment. Makes bad things taste better. Impress guests. Helps you quaff the shitty tasting potion.
Attentiveness
Enchantment, Self or Ally. 6 hours. Prevents drowsiness and keeps the mind focused. Good for long study sessions as well as long meetings. Useful in the field for remembering parts of dungeons, or that important persons name. Couple with the gracefulness spell below for Wizards who dump charisma.
Illusory Clothing
Always walk around naked. You're a wizard. You don't need to wear clothes! Can turn into a perfect replica of any outfit that you know fairly well. Great for disguises and such. Realize in horror that the supermarket has an anti-illusion field and that you can never return there.
Percy's Protection from Rain
Like an umbrella, but instead a haughty abuse of the mystical powers. In combat: there are plenty of things that work just like rain but are far more lethal.
Brett's Bubble Bath
Relax in any body of water with a rejuvenating and magically infused soap/bath salt enchantment. In a water environment can act as a bubbly Fog Cloud with a reflex save to get soap in their eyes, blinding them until they can wash it out.
Level 2-3 Spells
Enchantment. self or area, Pushes dust out of a fixed domicile, making housekeeping problems into grounds-keeping problems. Lasts for a week. In combat: could be a fast way to defend against assholes who throw sand. Can be used to clean out sections of a dungeon if you're worried about fires and sneezing.
Gracefulness
Enchantment, self or ally. Calms the nerves and works to prevent tripping and other cases of spaghetti spilling. +2 Bonus to diplomacy check to not make a fool of yourself. In combat: would give +4 bonus when dealing with difficult terrains or slippery shit. How many important wizards use this spell daily? More than you'd think.
Bug Zapper
Enchantment. Self or ally. 1d4 Electric damage to any small creatures that come in contact with you like the modern invention. Won't hurt anything larger than a humming bird. Good for fending off malaria, great for giving you immunity to insect swarms.
These are dumb and probably covered by better spells in whatever game you're playing. But I like to use stuff like this to remind the everyone that the arch-lich hates spiders just as much as everyone else.