When it comes to overstriked coins, I believe I have a few nice pieces, although they are not the best overstrikes that might exist out in the Russian copper numismatic field.
These two are the following examples of Anna overstruck on Petr I kopeks:
1730 1 denga overstruck on 1717 1 kopek:

1731 1 denga overstruck on 1716 MD 1 kopek:

What I am missing is an Anna polushka overstruck on the 1728/29 kopek series.
What appears next is probably a bizarre epilogue of overstriking events:
1757 2k over 1756 baroque 1 kopek over an unknown Krestovek

Another example is this, but with three clear visible years:
1759 2kopeks over 1755 baroque 1 kopek over 1727 Krestovek 5 kopeks!

The rest will be the common 1762 and 1796 overstriking event



There seems to be other rare overstruck copper coins, which involves patterns, but I would not dare to come across it yet because of the price factor.