Proofreader
Approve or reject 100 suggested edits
However, considering the fact that one needs 2,000 reputation in order to do so:
I feel like a Silver badge is much more appropriate. After all, once you gain access to this, you're essentially an established member of the community.
Other sites such as Writing.SE have the much lower needed reputation (1,000 for Writing.SE) for reviewing suggested edits, and I think this is one of the reasons for it being carried over as a Bronze badge.