Overall, City's Blessing Art Series can see play in the right context, but its effectiveness will heavily depend on the specific deck composition and game plan
Some had effects that worked the same but cared about different colors, while others had different effects based on the color it referenced
(Create an Incubator token with X +1/+1 counters on it and ": Transform this token." It transforms into a 0/0 Phyrexian artifact creature.) Whenever this creature enters or attacks, mill two cards, then incubate X, where X is the number of creature cards in your graveyard
You'll have all the card draw you could need, and be able to pump up a flier with +1/+1 counters to make a potent, evasive threat
Each upkeep, you put an age counter on your card, then pay the cumulative upkeep cost for each age counter on it
Durnan is a Green, 4-drop, 3/3 that, when he swings, will dig four and let you exile and cast a dork from your library with undaunted, and choose a background