A genre spawned by Dwarf Fortress, the recipe has been migrated to many settings, mostly simpler games, with a more moderate learning curve. These games are different than 'God' games, as you don't directly control the world, different than 'city-builders', as the scale is much smaller, and different from RTS/strategy games, because in most cases, you don't directly control the agents.
There are a growing number of games that don't quite fit into the existing genres. This is a thread that tries to bring discussion of such games into a central place - although discussion on individual games can also be found in dedicated threads.
While Dwarf Fortress my be the biggest, most in-depth and possibly the Father of this type, many people find it hard to get into the game, work out the mechanics, or deal with the ascii nature. A number of 'clones' have sprung up, each taking a slightly different path.
A list games that mostly fit into this category:
Dwarf Fortress - GWJ Thread - Official Site
Gnomoria - GWJ Thread - Official Website - Steam link
DwarfCorp - Official Site - Kickstarter
RimWorld - Official Site - Steam Greenlight
Spacebase DF-9 - GWJ Thread - Official Site - Steam Link - DEVELOPMENT CEASED
A Game of Dwarves - GWJ Thread - Official Site - Steam Link - Possibly Disbanded?
Prison Architect - GWJ Thread - Official Site - Steam Link
Clockwork Empires - GWJ Thread - Official Site - Steam Link
iubes - Official Site -
1849 - Official Site - Steam Greenlight - IndieGameStand Link - Steam Link
The Spatials - Steam Greenlight - Official Site -
Older games that may still be worth a look:
Startopia - Steam Link - GOG Link -
Sims: Medieval - Steam Link - Origin Link -
Space Colony HD - GOG Link -
Evil Genius - Steam Link - GOG Link -