Answer: It's a testing chip. It goes through the metal detectors to ensure they're working. There's a problem here though. You send X number of testers you get X number back. If you get X-1 or some other number you stop the line until you find your chip. The entire purpose of the test is to make sure that stuff like this--which is supposed to simulate a foreign object--does not get through. There's usually paperwork to document this. Write to the outfit and tell them what you found and rest assured there will be a s**tstorm on the other end.

Answer:  It's Stafir Móti Aðsókn an Icelandic magical sigil/stave to protect against ghosts and evil spirits

Answer: An apprentice final piece before becoming a journey man engraver.

Answer: It's a part of a ring warn by somone important on one of the shipping companies in the 18th century

Answer: It's the top (closure part) of a purse or small handbag.

Answer: These were how old reflectors were made, like for railroads

Answer: It looks like a plantation/planters chair. You’d put your sore swollen legs up on the arms after sitting on a horse all day, like a pregnant woman with her legs up in the same fashion. This is why the back is so sloped as well. If you sit up straight it wouldn’t be comfortable to put your legs up like that, but in a reclined position it’s good for blood flow and air flow.

Answer: Before construction, they are required to look for sites of archaeological interest. This is the pattern that they use to search for those. They trench a line and the dots on each side of the trench are the dirt which has been removed

Answer: Sugarcube holder.
For tea parties with scones.
Or coffee and cake.

Answer: I think it is a light sensor that can be turned on and off. When on the clock will not make chime noises unless it senses light. This way at night it does not wake people up.

Answer: This is a thermometer. My grandfather had the same exact device. Look at the number where it aligns with the convex (upper) portion of the plane, that should be the approximate temperature in Fahrenheit. I was always told to not spin it because it would mess with its accuracy

Answer: Pieces from an art installation http://www.dianathompson.net/2nd_Nature/kag.html

Answer: Yea ! It’s a thing ! Called trench art , google it there will be tons of beautiful engravings on shells

Answer: It's a so called "Schultüte". When children have their first day of school, they get it filled by their parents with gifts and sweets

Answer: It’s a bee and bug house, it’s filled with different materials for lone bugs to overwinter

Answer: Blind people and their walking stick.

Answer: the roof plate of a drum fish

Answer: It looks like a Davis Quadrant or Backstaff, a navigational instrument predecessor of the sextant. Maybe you should take that to a museum, with nautical expertise

Answer: I had one of these in my kitchen and I loved it! It was near my regular sink so I could pull the faucet head over to fill the “pot” then I would turn it on to boil the water. It has a pot that goes inside it that has holes in it - like a strainer. You put the strainer inside the “sink” and then toss your items that you want to boil inside the strainer and cover it. Once your food is cooked you lift out the strainer, flip the switch and all the boiling water drains out. The biggest advantage was not having to carry a large pot of boiling water over from your regular stove top to the sink to drain out the water. I used it for boiling pasta, potatoes, corn on the cob and I loved it!! I started to have trouble with it not holding water and when I contacted Kohler the said so sorry, but the model was discontinued. It was great while it lasted!!

Answer: Looks like an Artist’s Cabinet or Flat File. It’s a set of drawers for storing drawings, architectural plans, etc.

Answer: Looks like a polypore fungus that is exuding excess moisture, called guttation.

Answer: It's called a germ key

Answer: Former CATV tech here. It's called an expansion loop. Coaxial cable (for cable tv) is mostly aluminum which expands and contracts with temperature changes moreso than the steel supporting strand to which it is attached.
If this expansion loop wasn't there, the cable would literally suck out of the compression fittings in the Winter and kink in the Summer.

Answer: Water level indicator - limnigraph

Answer: Magic Lantern glass slide

Answer: I think your grandfather might have known someone in the Navy. Those are used in a ceremony when crossing over the equator. So I think your grandfather is what you refer to as a shellback. That is someone who's been over the equator.

Answer: crab pearl

Answer: Han Solo’s lucky dice

Answer: it is a 3D maze. Used in kid's camp or other outdoor activity clubs (Paintball, Airsoft, Trekking, etc.)In a paintball setting, it could be used to hold a flag or another capturable objective.

Answer: It's a herb grinder (mostly for weed).

Answer: Hasbro produced a Monopoly mini-game in 2009 called Monopoly: Get Out Of Jail. It looks like these were the game pieces used.

Answer: Looks like a scriber. They're used to make lines or marks on metal, wood, or a number of other materials. That looks like a metalworking one to me but may not be that specific.

Answer: He's partially deaf. It's basically a giant hearing aid (sound amplifier headphones).

Answer: Just a guess, but maybe built during the 70’s energy crisis. A home near where I grew up was built with a berm around most of it to save on heating and cooling

Answer: Picking out specific targets for ground police. It’s easier to track an individual through a crowd from above. This may be because they are armed, or something else that makes them high priority. Snipers are out of the question, firing into a fast moving mass of people would only end badly.

Answer: These are jyotish tokens with the Rahu yantra to be used for a Rahu Ranga Mantra recital and practice. Likely for personal gain.
You are right that these are magic squares, but more specifically they are called Navagraha Yantras. There are traditionally 9 of them (one for each "planet"), each having a distinct combination of 9 numbers. Together they can be combined to form their own "Magic square".
The words on the bottom are some form of either:

• om raam rahave namah
• om raag rahave namah
• or simply, om rahave namah

Answer: It’s a Masonic Square and Compass! You’re supposed to spin it really fast and you can see it

Answer: Sea hare eggs

Answer: This is sort of like the way you would package mushroom spores. Golden teacher aka GT is a popular strain of psychedelics