From my massive word doc of ideas culled from various websites and forums over the years: (I have tried to keep it to more adult ideas but a few kiddie ones may have crept in - apologies!)
Mulling spices
Flavored coffee creamers
Chocolate covered coffee beans
Chocolate dipped spoons
Coffee gift card
Candy store candy (put in plastic ornament balls or cellophane bags)
Lottery tickets
Coffee mug
Christmas ornament
Christmas cd
Small nativity
Small Angel
Christmas decoration
Book
Cozy socks
Book mark
Small jigsaw or sliding puzzle
Brain teaser type puzzle
Rubiks cube
Gel pens
Markers
Art supplies
Marbles
Poker chips
Video game
Memory card
DVD
CD
Music gift card
Computer jump drive
Watch
Inexpensive kitchen gadgets /tools
Oven mitt (cloth or silicone)
Wooden spoons
Recipe cards
Small cookbook
Holiday shaped/scented soap
Nail/pedicure accessories….nail gems, stickers, buffers etc.
Nail polish
Pumice stone
Eye pads
Facial masks
Foot scrubs
Bath bombs
Bath scrubbers
Soap dish
Bath pillow
Deodorant
Shaving cream/razors
Lotion
Nice soap/scented body wash
Bottle of cologne/perfume
Shower radio
Car air freshener
Tire gauge
Car cleaning tool/brush
Cleaners/wipes for car
Pocket calendar
Address book
Key chain
Small decorative boxes
Film and/or disposable camera
Picture frame
Small photo album
Pastels or oil paints
Brushes
Bottles of craft paint
Modeling clay
Beads
Jewlery charms
Jewlery making supplies/string
Small notebooks /notepads/sticky notes
Diary/journal/planner
Skateboard stickers
Skateboard wax/gum eraser/grip tape
Can of soda, Monster energy drinks, Gatorade etc.)
Accessories for ipod….skins, earphones, car charger etc.
Baseball
Small Football
$5 gift card to coffee shop, Target, drugstores, etc.
Unusual pen or pencil
Scrapbooking glue or supplies
Rubber stamps/ink pads
Thank you cards
Stamps for thank you cards
Silver dollar
Chocolate coins
Batteries to match Christmas toy
Cake decorating tips
Cookie/cake decorating sprinkles
Cookie cutters
Candy molds
Cake stencils
Christmas themed silicone muffin/cupcake pan
Lip gloss
Make up brushes
Cuff links
Puzzle book
Baseball hat or knit hat
Trail mix
Nuts
Beef Jerky
Protein bars
Can of Pringles
Snack foods
Bottle of champagne,
Chocolates
Gift certificate for flower shop
Calendar
Magazine of hobby or interest
Gloves
Scarf
Cd cases
Cookies
Chopsticks
Poster
Guitar strap
Guitar picks
Sheet music
Belt buckle
Sunglasses
Chain
Belt
Tennis balls
Golf items…balls,tees,etc.
Wine accessories/bottle stopper
Soda fizz keeper
Seeds for garden
Garden accessory….garden markers etc.
Flower cutters
Specialty craft scissors
Paper punches
Gift wrap supplies...ribbon shredder, easy tape dispenser, Gingerbread/christmas scissors
Gourmet sauces or spices etc.
Jams and jellies or flavored honey
Bag clips
Silly hat
Party poppers
Gag gift
Giant candy bar
Movie gift certificates
Tickets to sporting event, or other event
Cereal box freebie
Sample items or other freebies
Tools or hardware (picture hangers etc.)
Paint buddy
Home improvement tool
Beefstick
Mini mustard jar
Bottle of beer
Bottle opener
Cheese knife set
Coffee syrups or flavored sugars
Small bag of coffee
Mini liqueur bottle
Candy shot glasses
Cocktail item or tool
Earrings
Bracelet
Ring
Small purse
Wallet
Laser tag voucher
Winter themed boxer shorts
Windshield ice scraper
Hair accessory
Gum or jawbreaker
Candles
Fishing items
Camping items
Marshmallow skewers
Smores kit (in a bag)
Travel coffee mug
Reusable Water bottle
Reusable shopping bag
Christmas scented air freshener
Vase
Christmas lights
Snow globe
Make their favorite Christmas cookie or candy
Something to add to persons collection
Christmas pillow case
Cigar
Mouse pad
Glasses case
Eye glasses cleaning cloth (micro fiber)
Magnets
Kitchen towels
Napkins
Napkin rings
Tide to go pen
Small book of organizing tips
Tool (screwdriver, picture hangers etc.)
Flashlight
Pocket knife
Dried fruit
Nuts (flavored)
Pop corn seasonings/plain microwave popcorn bags
Silicone basting brushes
Kabob skewers
Accessory to decorate room
Wood letters that spell something or initials
Specialty ice cube trays
Bottled ice coffee
Pancake/egg mold
Pancake mix
Snowman decorating kit
Snow ball maker
Squirt guns
Popcorn balls
Gingerbread loaf or other Christmas bread
Framed photo
Handwritten letter
Homemade coupons
Any homemade item
Fishing Lures
Mini Keychain Flashlight
Sample Shampoo, Conditioner, Body Wash or Hand Lotion
Sample Men's After Shave
Flavored Lip Balm
Nail Clipper
Nail Files
Nail Polish
Chocolates or Other Candy
Wrapped Tea Bags, Such as Peppermint Tea