Here is a list of mods that can be used for transhuman era/ apocalyptic era/ galactic era ideas.
Genetic Era for Warlords -
http://forums.civfanatics.com/showthread.php?t=184182
Planetfall mod - basically an awesome port of Sid Meier's Alpha Centauri
http://forums.civfanatics.com/showthread.php?t=252829
Conflict on Chiron - a newly developing fork of planetfall - since planetfall's development slowed down.
http://forums.civfanatics.com/showthread.php?t=426026
Which adds the alien factions from sid meier's alpha centauri crossfire expansion and other goodies.
Star Trek Mod -
http://forums.civfanatics.com/showthread.php?t=233074
The Federation could be a new galactic civics - idea of future collectivism. There are lots of technologies to mine, from the mod and all the series also. Technologies I loved, transporters, warp drives, wormholes, temporal technologies, sub space, warp field shields, spatial distortions, the borg, androids, to name just a few.
Star Wars mod -
http://forums.civfanatics.com/showthread.php?t=157016
The idea of a galactic empire. whether old republic nice, or facist Empire could be introduced as a civic or Era unlocked new spawing countries. Lot's of new technology ideas here too! Lightsabers, sub light drives, holograms, landspeeders
Final Frontier Plus? - improvement of the Final Frontier official civ iv scenario.
http://forums.civfanatics.com/showthread.php?t=351012
new resources, technologies, events for the future eras? Pirate factions?
MOO2 Civ -
http://forums.civfanatics.com/showthread.php?t=267295
Mod based on technologies and aliens from Master of Orion 2. It would be interesting to take aliens and technologies from there. Loved the races and the incremental technologies from moo1 and moo2. Tech tree from the original games has an immense lot
Babylon 5 Mod project-
http://forums.civfanatics.com/showthread.php?t=261551
This project looks like it has some good ideas, jump gates, hyperspace, they have invested an extrordinary amount of time on ship graphics. Love the Minbari race
Not to forget the
Dune Wars mod -
http://forums.civfanatics.com/showthread.php?t=335213
Ships from the Dune books series look like the flying craft in the Disney John Carter (of Mars) movie.
and
Mars Now! -
http://forums.civfanatics.com/showthread.php?t=312246
both have units and technologies that have been developed
NecroCristi Mod- Apocalyptic mod.
http://forums.civfanatics.com/showthread.php?t=237238
might be interesting to have a fall of civilization/ apocalyptic era,
may have been caused by a virus, like Stephen King's the Stand or Amc' tv series The Walking Dead based on popular series of Graphic Novels.. Or more Mad Max like, like the breakdown of civilization through a scenario like peak oil, or even after nuclear war. Could be a masssive check for a civilization after things get stagnant. Disaster events could be triggered like volcanos, earthquakes, floods, The Great Earthquake that could destroy California or the landslide that could happen in the Azores/Atlantic Ocean, could be interesting challenges to gameplay. One of the biggest things that made Sim City fun was watching your city adjust after disasters struck. Rebuilding civilization not a bad idea for an Era.
Just an idea.