This translucent blue goop found in the forest near some running water:

1

"Looks like star jelly or 'astral jelly' to me! Weird stuff..."

This numbered, pointy wooden object on a string:

2

"The letters [at the top] are abbreviations for the names of colors in French, found on this page. As for what it is, though, I have no idea. Maybe some kind of divination or pseudoscience tool?"

"I think you are very right; it looks like a variant of an adjustable pendulum. There is a lot of love for pendulums in Southern France, where for centuries, the two most precious things were looked for with twigs, pendulums, and pigs: truffles and water springs. A huge variety of theories and esoteric stuff has been written about that over the years. The truffle site you found is a wonder of such scientific-sounding esoteric stuff.

This small metal object that was found in an antique jewelry box:

3

"Some sort of collar stay."

This pot with a handle on the side and a Red Cross emblem on top:

4

"It is called an invalid feeding cup."

"German here. My Grandma owned a similar one, which came out whenever someone was bedridden. It virtually eliminates the need to get the bedridden person into an upward position for drinking/administering fluid. As the patient, you simply put your mouth around the nozzle and then drink out of it — well, more like sucking on it, actually. Little to no risk to spill stuff, no matter which position your body is placed in."

This tiny metal object bound with a string:

5

"String and ring puzzle, though I think the string is tied wrong."

This expandable circle with a lid that holds it together:

6

"It's the top of an expandable purse; yours is just missing the actual fabric purse part. Here's one expanded with the purse."

These two wooden sticks attached to each other with a clear wire:

7

"It’s a circular knitting needle."

"I believe these are LYKKE Crafts Driftwood style 5” interchangeable needles."

A toolbox filled with some type of tool and tiny vials containing little metal pieces:

8

"Rotary wafer switch design, maintenance, and repair kit. The various metal bits fit into the flat, non-conductive wafers arranged along a circular path. The shafts connect the individual wafers to conduct electricity between the metal bits.

I've never seen a kit like this so well-stocked. Half a century ago, it was an inexpensive way to direct signals to multiple connections. Switches like these are becoming obsolete as digital electronics take their place, but you can still find them on low-level appliances like washers and dryers; many are still using the 'clunk, clunk, clunk' rotary switches instead of soft-touch push buttons."

"A rotary switch kit. You can make different amounts of poles and different amounts of positions. The manufacturer is CRL/Centralab."

This small black disc that clicks as it rotates clockwise:

9

"It's a Phonak CeruShield Disk. It's used to change filters in hearing aids. Pop your old one in the waste slot and take a new one out."

This small glass tube with a solid spike at the end found at a plant swap:

10

"It’s a floral water pick tube that’s missing the rubber stopper on top."

This small plastic container with a metal sieve inside:

11

"The oil container part for an oil brush."

12

These carved, wooden pieces found at a thrift store:

13

"These are ornamental spearheads. Back in the 1970s and 1980s when African/Asian artifacts were popular. They were available in stores that were predecessors to Pier 1-type stores. Reproductions were typically made in India."

This corroded, round piece of metal with writing on top:

14

"It is a part of this old bicycle bell."

This tiny, colorful dial with a wheel at the bottom:

15

"It's called an opisometer. The picture on the Wikipedia page looks very similar to yours."

"It is a wheel you put on a map to find the distance on the road. Different scales for different map sizes. You trace the route for the distance."

This tiny glass pitcher attached to a dropper with measurements:

16

"Vinometer."

17

"It is one of these. The page says, 'This is a World War II era direct reading reflector magnetic compass, Type 2 or 3 KAI, manufactured by Tokyo Aero Indicator Co, as used on Japanese Navy aircraft."

This large, mechanical tool found in an old industrial kitchen in Boston, Massachusetts:

18

"Apple peeler?"

"That’s definitely what it is. Here’s a video I saw recently of one being restored. Shoutout to Hand Tool Rescue!"

A domed opaque cloche from China someone received as a gift:

19

"It's a teacup. You flip it over and insert the ball top into the indentation in order to keep it standing."

This small metal cylinder found sticking out of the wall in someone's unfinished attic:

20

"That's an arrowhead lodged in your wall."

A glass and plastic item that was found in a box of dishes:

21

"It's the top of a pitcher."

"It's an ice core for a pitcher. You fill it with water and freeze it. Fill your pitcher with the desired beverage and pop this in. Keeps drinks cold on the counter for long periods without diluting them. I have a couple and primarily use them for juices during holidays for my family brunch buffet. You can see the gap for pouring in the rim (you're holding it upside down)."

This 7" long, wooden-handled tool with a pointy stone end:

22

"Sharpening stone."

This heavy, thin, pointy metal object:

23

"It's a carving tool for clay."

This 2-foot-long wooden stick with metal on one end:

24

"It appears to be part of a sewer-cleaning apparatus. This patent by one William H. Stewart shows what appears to be your object. That patent is for 'sectional rods specially adapted for sewer cleaning purposes' — this is one end of a rod that would hook onto the corresponding end of the next sectional rod.

Armed with this information, we find that there was a W. H. Stewart in Syracuse that made sewer cleaners. And suddenly, the hard-to-make-out text on OP's object becomes much clearer: it's '...CUSE, N.Y.,' as in 'SYRACUSE, N.Y.'

So I feel pretty confident your object is part of a sewer cleaner."

This wooden box that slides up, revealing only a small opening on the top:

25

"Cigarette dispenser. Fill up the box, lift the lid up and down, and it deposits a cigarette in the slot."

This vintage, belt-driven machine found at an estate sale:

26

"It's a riveting machine."

"You know the rivets at the corners of your jeans pockets? Installed by a machine like this."

And finally, this little metal item found in the pocket of an old jacket:

27

"Looks like the metal clamps that are used to hold papers flat in an old-fashioned office ordner, no idea what they are called (I'm not a native English speaker)."

"A binder compressor bar."