So this is my 20th post picking the brains of Tool Nerds to
help me identify some random items from the
garage organization/upgrade at the @gardenofeden.
Even after posting, there are still items we haven't been able to identify,
or if someone actually were, it's not clear to me with conviction that
the answer is true.
Please take another look at the things in question and see if
you have a definitive answer.

SUGGESTED: Something to clamp down a glass tabletop, a fastener for wood, a fastener for blinds, a fastener for furniture, bottom pieces to legs of a table, a paperweight, door knobs.

SUGGESTED: Face gear from an angle grinder, part from a lawn mower or small tractor transmission, a transmission from something that moves & runs on an internal combustion engine, ring gear and drive shaft assembly to externally attached to a case carrying a pinion gear, for making cool prints in dough or with paint on the edge of the wheel part,.

SUGGESTED: Some sort of support bearing for a long spinning shaft, a roller for a sliding door, a hand built adjustable bearing- maybe for a chain drive, an adjuster, set bering for a pulley, a roller for a hanging door

SUGGESTIONS: NONE!
SUGGESTED: a piece for a bifolding closet door, vacuum check valve, closet door latch, twist on coax connector missing the cap, fuel filter, O2 sensor, a girl robot's head!

SUGGESTED: a gear for some sort of device that has stopping points on both ends--maybe for a hand juicer, looks like it used to have a chain on it--maybe for something with a handle that you turn by hand to squeeze or squish something, a part for a car jack, a chain driven gear or chain tensioner for some sort of machine, similar to the gear on the throttle handle on an outboard motor, sprocket, one of the gears on a 10 speed bicycle separated from the rim, a turn of the 18th century gear selector from a motorized vehicle or farm implement
SUGGESTED: a laser pointer tip, a plumb bob, a device used to pop a tempered window
If you have any input that could clarify the WTFness of any of these items,
please chime in!
Be sure to note the # of the item you are commenting on, and tell me:
1. what it is--please be specific--I don't know about these things!
2. what it's intended to be used for
3. if it still looks useable for its original purpose
4. alternative ideas on how to use it.
It's so fun to play this game with you and tap into your knowledge and/or creative minds.
I'm still sorting through the garage, so who knows what else I'll find!
Thanks for tuning in!

Lol
#10 looks like some strange kind of Allen key of sorts...but wouldn't be able to tell you for sure. It looks OLD.
#15, I think I have to agree with the door thingy thingy...lol.
#3. I know I've SEEN this somewhere before, but no clue where.
The rest? Uhmmmmm...no, beats me.
Sorry, I'm not a very good help haha. And there was me thinking I had some handy traits (as in working with 'manly' tools etc.) I guess not.
@tipu curate
Funny how our ideas of ourselves can be shifted in one little moment!
Super glad for your input even though nothing is really solidified @misslasvegas!
#10 is definitely old, super heavy--like something someone would make to actually last!
This was a pretty enticing and likely the most sound answer on FB for #15: Twist on coax connector. Yours is missing the cap. It goes on the ends of coax wire. Coax goes between a CB or Ham radio and the antenna. These connectors solder or crimp to the ends of the coax and screws to the radio and antenna.
What do you think about that?
But the thing in 15 is different from this thing in this photo?!
When I see this one, with the explanation, I go: Yes! Exactly, that's it! But the photo you have is something different. Right? Argh!!! I don't know! So frustrating to even try figuring these things out LOL.
I think what he is saying is that the thing pictured in #15 is the inner cylinder, and missing the outside cap. It is definitely hard to know what is and what isn't, but it's a fun game picking people's brains to see their perspectives. Thanks for giving me yours @misslasvegas.
You're welcome @everlove, and thanks for the post. It's like a jigsaw puzzle but different haha. And I might learn a thing or two. Yes, people's perspectives can be very different. I see these things and think: Yup, seen it somewhere, but where? No, that's not it...uhm...LOL. It's fun :)
Sounds a bit like my process too. Maybe it's that I've seen these things floating around before and never knew what they were, or maybe I have seen them in context with what they were intended to be, and just can't put my finger on it. So glad to have other's brains to pick, and to put the pieces in place together. I appreciate your presence here @misslasvegas!
Upvoted 👌 (Mana: 0/3 - need recharge?)
Thank you dear @tipu!
Way out on the limb I'm going to throw out for #10 a possible heat sensor?
Well regardless if you are right or wrong, you're still the only one who even went out on the limb @bitshares101!
Any suggestions what heat it would sense? Seems something would have to get really hot to make change in this really dense metal.
Closest thing I came across
All-SiC probe and high-temperature thermocouple under oxy-acetylene flame thermal and localized thermal-ramp joint test with temperatures reaching 1600 ı C
https://www.researchgate.net/figure/All-SiC-probe-and-high-temperature-thermocouple-under-oxy-acetylene-flame-thermal-and_fig3_249516289
OH!!! now this looks promising! I did get a welder from my brother and am not totally savvy at how they work, but this would seem to make sense considering the density and patina look it has. Thanks for the input @bitshares101. I'm going to check in with my brother and see if he can confirm!