I've been dreaming with sources for science.
Ancient Era.
What do we do the very early game? We explore, we meet other civs and CS, we fight barbs, and plow a farm or two.
All those could be sources for science.
+ 1
every two tiles explored
+ 10
every first meeting
+ 10
every destroyed encampment
and a flat +5
for Palace
But then, if we ever start in an isolated island, with no place for barbs spawn, we would be incredibly backwards, as realistically would be, but it isn't going to be fun. The only assets those cities have is their population, but without a library they can't improve science. So an unemployed pop might produce some science (and other things, to make up for the growth lose and unhappiness).
Unemployed: +1
+1
+1
+1
Or the Palace can be given a special feature that gives just this if there is unemployment in the capital. (so more than 1 unemployed pop won't be good).
Classical Era
Now we have some buildings. Library is obviously a good source of science, but others that could help a little may be the shrine (because faith people sometimes discover something) and the forge (because engineers usually help developing techs).
Mid game
For science focused civs, Caravans and Cargos may be allowed to "move" science, like they already move food and production, once library is built. This represents that the civ is spending money in research, for the gold it isn't earning from the trade route is going into beakers. OCC may require some puppets for that to work.
For diplomatic civs, their science production (and culture and units) is mostly coming from allied CS, and from trade routes to a more advanced civ.
Cultural civs don't produce as much science, but they have access to most wonders and social policies. Trade routes to a culturally influenced civ will give more science and gold than usual.
Military civs can replace the +X
for killing an enemy unit for some amount of
. So, for a military civ, constant warfare is a must to avoid falling behind. They also need to produce more gold than before, with trade routes or pillaging.
Late game
By Modern Era, science civs will advance too fast compared with others, but it won't be enough to stop others from victory. With no time to build an army, no time to complete buildings (just the hammers for spaceship parts), no access to most of wonders, lower gold production (foreign trade routes are unprofitable), science civs can still achieve a science victory, but others will be uncommon.
