Salve milites!
Today i want to show you all of the console commands, with their effects. From A to Z.

But first:
- To open the console press the button below the "Esc" button.
- You can't earn achievements while using these commands, even if you enabled iron man mode.
- The symbols ( - ) in front of the commands are not needed.

Now, the commands:
- ae [<amount>] (Modifies your aggressive expansion. For example: ae -10 would reduce it by 10.)
- annex [<countrytag>] (Annexes the specific country.)
- army [<cohortcount>][<province>] (Adds specific amount of units in selected province.)
- army_loyalty [<prov> <amount>] (Sets army loyalty to specified amount.)
- cash [<amount>] (Adds specified amount of gold.)
- centralization [<amount>] (Sets centralization to specified amount.)
- character.age [<id>] [<age>] (Sets character age.)
- character.martial [<id>] [<value change>] (Sets character martial, replace with zeal, charisma, or finesse for those.)
- civil_war [<countrytag>] (Starts a civil war in the specified country.)
- coat_of_arms [<countrytag>] (Prints the script for the country's coat of arms/flag to logs\games.log.)
- conquer [<provid>] (Conquer specified territory.)
- control [<provid> [<countrytag>] (Control specified territory by specified country.)
- debug_mode (Shows tags and Ids)
- debug.achievements.resetall (Resets all achievements)
- declare_war [<countrytag>] [<countrytag>] (Starts war between two countries.)
- destroy_mercenaries (Destroys all mercenaries on the world map, but does not prevent them respawning.)
- eagerness [<countrytag>] (Check AI eagerness for war.)
- event [eventid][target] (Triggers event for specified character/province/country.)
- exile (Exiles selected units.)
- explorer (Opens the object explorer debug tool.)
- forcepeace [<countrytag>] (Forces AI generated peace offers for specified country.)
- fow (Toggles fog of war on/off.)
- gui_editor (Opens the GUI editor.)
- horde [<province>] (Spawns a barbarian horde of 100k units in specified province.)
- instantbuild (Toggles on/off instant build.)
- instantmove (Toggles instant move on and off.)
- instantpopassimilation (Toggles instant cultural assimilation of all your pops on monthly tick on and off.)
- instantpopclass (Toggles instant promotion and demotion of all your pops on monthly tick on and off.)
- instantpopreligiousconversion (Toggles instant religious conversion of all your pops monthly tick on and off.)
- instantsiege (Toggles instant sieges on and off.)
- instantwar (Toggles on/off instant war declaration.)
- kill [<id>] (Kills target character.)
- legitimacy [<amount>] (Modify current ruler legitimacy.)
- corrupt [<amount>] (Modify current corruption to amount. Defaults to 100 corruption.)
- make_child [mother] [father] (Spawns a child for the specified parents.)
- manpower [<amount>] (Add specified amount of Manpower, note that the number is taken in thousands so "20" would result in 20,000 manpower.)
- marry [character][character] (Arranges marriage between two characters.)
- military_experience [<amount>] (Modifies your military experience.)
- music.next (Changes current music track.)
- navy [<shipcount>][<province>] (Spawns specified amount of Triremes in province.)
- observe(ob) (Switch to spectator mode.)
- portrait_editor (Opens/closes the portrait editor.)
- political_influence [<amount>] (Modifies your political influence.)
- prestige [<amount>] (Modifies your prestige.)
- revolt [<countrytag>] (Starts a revolt in specified country.)
- settings (Opens the debug settings.)
- setup_editor (Opens the province setup editor where you can edit culture, religion, etc. This creates a setup file in documents that overrides base files.)
- stab [<amount>] (Modifies your stability. Default sets it to 100.)
- tag [<countrytag>] (Switch tag to another country. All countries have a numeric tag and an alpha-numeric tag. Either will work.)
- tech [<amount>] (Gives tech levels. Amount is optional, not specifying the amount gives 1 tech level. Does not unlock inventions and may make it impossible to do so.)
- ti (Toggles terra incognita on/off.)
- tyranny [<amount>] (Modifies your tyranny. Tyranny -10 would reduce it by 10.)
- tick_day [number of days] (Advances time by the specified number of days.)
- tweak fow (Opens the tweaker GUI to enable or disable Fog of War.)
- warexhaustion [<amount>] (Modifies your war exhaustion. warexhaustion -10 would reduce it by 10.)
- yesmen (Activates yesmen (AI accepts all diplomatic proposals).)

I hope my guide was helpful.
I am sorry for the potential grammatical mistakes....
My source was the official Imperator: Rome wikipedia.