personally, i'd recommend these types of sounds (i don't have any examples presently): you could probably just physically record yourself clicking on a mouse button and amplifying the sound to make it more distinct for UI button sounds iirc, some games have had the sound of coins clinking (or something similar) for technology completion, though that may be more fitting for a market a rousing cry (kinda like what the Spartans yell in 300) would probably be good for phase advancement, perhaps even varying between civilizations if that's possible. it could perhaps be that civ's word for, "Onward!" as in "onward into the future", or an equivalent word or phrase ("Forward!" "Let's go!" "Success!" "Yes!" "Hurrah!") actually, now that i think about it, maybe it would be a good tribute to the entire cast for everyone who contributed to the final game and is available to do so to just submit a recording of themselves shouting "Hurrah!" or otherwise cheering and compiled together into a single sound effect for phase advancement across all the civs [*]similar to the above, a cheer would probably be good for when heroes are trained. if possible, there could be varying ones for each hero or for each civilization in their respective languages, or just in English. the onlye xample i can think of is "Hail Caesar!" if Julius himself is a hero (i can't remember if he is or isn't) [*]ominous chanting would probably be best for the wonders, something to evoke awe and mystery in fact, since i've mentioned it, maybe "collective" cheers and other such sounds would be good "neutral" sounds where applicable