The first government, Republic, also gives an economy boost of 10%.  You'll see it when you research the government type and select it from the change government box.

Stock market and the preceding techs in that line all give you an income percentage bonus, but you usually won't see much of a difference in your overall earnings unless you stack them. One per planet usually isn't anything to brag about unless it's a very high population planet or already has very good income.  If you add one 20% bonus structure to a planet making 40, you're not exactly on easy street.

Trading gives you extra money, and researching to higher levels of trading gives you a trade income bonus in addition to opening up more trade routes.  If you do trade routes, build economy starbases near the planets listed as your route starting points.  Again, researching higher levels of trade will open up more starbase bonus modules.  Load traders with enough life support to send them as far away as possible. 

It's also a good idea to make extra traders and park them somewhere, because trade planet invasions, and most wars, cause the route to be canceled and the trader you started it with vanishes from the game.

Morale techs sort of indirectly increase money by helping your planets populate faster and, at higher levels, allowing you to raise taxes. I usually try to get some form of fertility acceleration for the population growth bonuses though.

Recruitment centers give you a 10% bonus, as do other one per planet improvements in different racial tech trees. Sorry, I've been playing the DL campaign the last month so almost all I can think of right now is Terran tech.