Because modern cities are so crowded, it's important to be able to quickly generate NPCs, locations and conflicts. Thus, I use table supplements like:
Fishwife Games' Modern Crime Lists.
One of my favorite "name lists" supplements of all time: Everyone Everywhere from Erik James Olsrud.
A Small Collection of Flowers and Entanglements from Aether Corp - good for character based drama. Use these to create a complex situation that you can then throw comic book stuff at.
Wiseguys, from Just Insert Imagination, a Savage Worlds supplement about organized crime.
The Location Crafter from the Word Mill is something that just popped onto my radar and I'm already very impressed with the methods used to develop locations there. Looking forward to using it going forward....
Here's some links to each of the various systems I used in direct play of the anthology (you can also find these in the index of games):
The Adventure! system from White Wolf games. A new edition from Onyx Path based on their Trinity Continuum system, which I find much improved, recently released and I'm looking forward to getting the new edition in...
Savage Worlds system, much aided by Jason Blair's Streets of Bedlam supplement. (Savage Worlds also now has a new edition.)
The Leverage RPG is no longer available but the updated version of the game is, at CortexRPG.com.
Feng Shui 2ed., the Hong Kong action movie RPG, very good for swarms of ninjas.
Fate Accelerated, (Free Downloads, SRD) has become my staple for the game for many reasons. I'm using the approaches that were established in Filamena Young's White Picket Witches campaign setting, available in the Worlds on Fire supplement.
Cartel by Magpie Games was the basis for my Gotham City PD undercover squad game. Cartel is a game about criminals, so it was perfect for the lawless GCPD of Tricorner Island.
Operators was the basis for a solid action game....
Cypher's First Responders was a fun one-shot...