Although other people have already correctly identified your finds, I figured I should still go ahead and post the reply I typed before you got any other replies. Somehow, my reply didn't get posted. A few minutes, ago I checked this thread to see reactions to it... and saw my reply wasn't there!

So, although it's several hours late, here it is.
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Your first two photos show a brass keyhole-cover (also called a dust-cover) from an antique "Smokehouse type" padlock. The marking on it saying FB&Co. represents an unknown manufacturer. To see photos of two complete examples of FB&Co. Smokehouse-type padlocks, go to the link below, and scroll down to the two FB&Co locks.
Time-dating them correctly is difficult due to FB&Co. being unidentified... but based on the form of the lock with a ring at its bottom and the modern-ish keyhole on the other lock, I think (I do not KNOW) they date from the late-1800s into the early-1900s.
The object in your third photo is a suspenders-strap adjuster buckle, also from the latter-1800s into the early-1900s. There are many-many variations, but I was able to find a photo of one which is quite similar to yours. (Note, it shows what the little "tongue" on yours was for.)