A whole lot of "what is it?"

[Bitdrop]

A finial of some sort? Has a checkered pattern on it and the hole goes all the way through. The base of it has a indented ring wrapping all the way around.



Buckles, buckles, and more buckles.



Lead bag seal? Game piece (checkers)? Smashed bullet? Sinker? About the size of a quarter.



Button? Looks as though some sort of cabochon rested inside of it.

 

[duggap]

Your last one is a bridle rosette.

 

[cudamark]

Is the first item threaded?

 

[Bitdrop]

Is the first item threaded?

It is not

 

[ARC]

#1. Finial part / spacer.
#2. various buckles obviously.
#3. Lead seal
#4. Bridle rosette as mentioned by Duggap.

 

[Goldiver]

Your "finial" piece appears to be part of a decorative brass tip found on military shoulder cords or aiguillettes. These tips are two piece, the cord sewn to the lower piece while the smaller top piece rests on top to cover up where the cord was sewn to it. There are many different designs from fancy to plain brass.

http://aufildesmotsetdelhistoire.u.a.f.unblog.fr/files/2010/08/aiguillettes.jpg

http://www.antikcostume.com/images/1500/-22270.jpg