Half of the COD 4 maps were absolutely perfect for Call of Duty gameplay, and the other half weren't too bad for the most part. I specifically remember really liking: Backlot Bog Crash Crossfire District Overgrown Vacant I've always considered making some COD 4 maps in Forge, but none of them have ever really translated well to any of the Halo games. Of the ones I listed, maybe District, but not for Halo 5.
Assuming we're sticking to shooters. Destiny - Shores of Time, Pantheon, Bannerfall, Exodus Blue, Firebase Delphi, Dungeons, Rusted Lands Jedi Knight Outcast - Warring Factions, Garbage Facility, Bespin Streets, Death Star, Temple Tournament, Bespin Exhaust Shafts, Imperial Garisson Metroid Prime Hunters - Processor Core, High Ground, Fuel Stack, Ice Hive, Outer Reach, VDO Gateway
Final Destination and Hyrule Temple from melee --- Double Post Merged, May 1, 2016 --- All of literally any valve game. Specifically, portal 2. Either half life.