That looks like valve stem caps. Remove the rocker cover and have a look to see if some are missing. It’s not that uncommon ( my 300 had some similar debris in the sump)
They are easy to fit new ones - slacken off the rocker and new caps can be dropped onto the top ov the valve stem.
The bigger bit at the bottom of the pic in 2 halves looks like it may be the remains of a stem seal. Slightly more involved to replace. Of course, it may all have been rectified in the past and the debris just left in the sump....
Rich