I saw something similar to those that was attached to the rim on a Premier snare, but it was one piece, not multiple.

That could be marching drum hardware but not sure if it's Slingerland doesn't look familiar to me.

Looks to me like home hade parts and peices of hardware and other bits.

I'm also thinking they're marching drum hardware, but, like you, they just don't look familiar. Hopefully, someone can ID them!

I'm thinking the same thing!

They look homemade to me - hardware store parts. But I would say they are almost definitely marching leg rest brackets for snare drums...

It looks like you've got pieces from four pipe band snare carriers made by XL Specialty, who provides equipment to Ludwig, Premier, and Mapex. They used to do Yamaha marching hardware as well in the '80s and '90s.

The parts at the top left are called angle bars. They use those F-clamps to attach to the edge ring (aka collar) of a free-floating or high-tension marching snare or pipe band snare. There's usually another piece bolted onto the angle bar that mates up to a harness attachment.

The L-shaped parts at the lower right are used to attach angle bars to snares that don't have the edge ring or collar of a high-tension marching snare. These slip between the head of a tension rod and the hoop.

The plastic caps at the lower left are normally used on the lower arms of a bass drum harness, preventing those aluminum arms from damaging the drum's finish. They also happen to be used on one particular type of pipe band snare harness.

You can see all these parts in XL Specialty's parts catalog. Go to this web page and click the PDF link titled "XL Snare - Lower Assembly".

You've also got some sling hooks there in the upper right. Slings are still fairly common for use with Scottish-style pipe band snares.