I've done most of mine; I still want a Sulla portrait denarius (how much does a decent Fine one go for nowadays?), a Constantine III siliqua (on the edge of realistic), a Carausius Denarius/Argentius (a few years ago, one turned up on vcoins for c. 700 - I should have bought it!) a Eugenius and an Alexandrian Hadrian Drachm with a smooth, glossy chocolate patina. Oh, and I'm probably mangling the Italian title, but the book Le Preziose Patina. I remember reading it at my college library (the librarian is a Byzantine expert (hopefully he's still with us ). Perhaps someday a decrepit Priscus Attalus AE3 will turn up at auction (Judy Tenuda voice; it could happen!). That's somewhat outside the bounds of realistic, but weirder things have happened. Although it's a tiny subset, patina collecting is one of my collecting interests.