Found some pennies during my last CRH that have the strongest toning I've come across. They're 2 x 2019 d 2014 I think they're interesting let me know what you think. .
I like the top 2019 D. I'd save it in a flip even though it will probably never be worth more than one cent.
The problem with the zinc cents, they react and tone very easily. In a few years they will be indiscernible globs of metal. While I am not a huge fan of toning, I favor toning on copper cents to zinc cents by about a billion to one.