This site has 15 cute ideas: https://wonderfuldiy.com/old-keys-upcycling-projects/
Here are a bunch of fun ideas https://www.hometalk.com/search/posts?filter=Keys%20in%20Upcycle
If you make a pegboard with a frame, you can paint it to go with your style in the family room, kitchen, laundry room or back porch. You can distress the pegboard and frame, or shine it up with fake gold flakes and a glossy sealer. Put a peg in the board for each key or set of keys. You can paint or polish each key before you put them in the board. You can even wash the keys in dishwater with a little vinegar to remove grime. I hope you get lots of great ideas, Kelly. I’m going to do this one myself! ☺️
Clean them & use them in wind chimes. They make wonderful tones as they gently bump metal tubes, glass, porcelain objects or pieces.
We made a wind chime using our extra keys!
Another popular trend is stamping a word on the key (like "strength" or "prayer") and putting it on a chain to wear as a necklace. It could make a great Christmas present for friends and family members!
Use for Valentine messages: "The key to my heart" or "Okey - Dokey" You're for me.