The world is full of wonders. Some of them are natural, others man-made. A strange device found in the attic or bought at a yard sale may leave you scratching your head for days on end until you figure out its purpose. When you tap out after an umpteenth Google search that turned out to be fruitless, you are left with only one option: Internet know-it-alls to the rescue! Forum and message board users love to solve mysteries and often have domain-specific knowledge that you need to find the answer.
1. This tool used to be from my grandpa. Thinking about pincers but the ‘twisting mechanism’ is odd

It’s a hand vise. Used in jewelry and watch repair. Not intended to be fast.
2. For context: It’s in a dentists office

A very old dental drill.
3. Found in Madrid Airbnb. Some sort of board game with dice and chips

This is Parcheesi.
4. Spin the handle and the fingers click, what is this?

It’s a wooden tapping hand toy. Seems to be called “impatient fingers”:
5. This old container I found at my grandma’s house, its the shape of a pineapple and opens up to show a tiny spoon

It’s a novelty personal salt supply.
6. What is this w-shaped, chain-suspended rope thingy?

This is the sort of structure to grab on to in case anyone happened to fall in the river.
7. Found this in my house. I bet my wife it has something to do with a tie. Do I win?

Hoof pick for cleaning horses hooves.
8. What is this clothing item and how does one wear it?

You have to tie it in back first then wrap the back around the front to tie the front. Like this:
9. Found those things on my parent’s garden, it looks like eggs, it’s very squishy

Looks like it might be nostoc, a cyanobacteria.
10. Found on the street in a residential area in Australia. Top button makes a loud “click” when pressed in

Dog “clicker” for training them
11. This thing I found at a thrift store, when you pull the handle something winds up inside

Camera shutter timer.
12. What are these swirly things? Found on Google Maps – located in Cogdell, Georgia, USA

Checked the tax records… It is or was an alligator farm.
13. When you pull the ring on this, four little pins come out. What is it used for?

It’s an anti-theft device for pocket watches. When the watch gets pulled, the spikes extend, preventing loss, and well, notifying you as well.
14. Metal part with a finger loop possibly?

It is a detail from a trumpet.

15. Do workers mom found this in a box in the attic

Phurba, used as a ritual implement to signify stability on a prayer ground during ceremonies.
16. Found these two things inside my 2002 Toyota Celica in the morning

The metal rod on the left is a thing called “salai/Baj” used by turban-wearing Sikhs to tuck in hair around the turban. The one on the right was just a pin from a monitor stand!
17. Found this small swiss brass box from outside a few years ago. Still have no idea what’s it supposed to be

It is a portable ashtray.