As mentioned before, in earlier editions alignment had mechanical effects. (e.g. detect evil, protection from good etc)
stuff, that I rather disliked usually …
unless when there was a campaign build around that concept
e.g. I once ran a Pathfinder campaign, that ran strong on the LE theme
(contract with devils, convincing a dragon to abduct a princess, etc …)
some official setting examples:
Tékumel (the D&D-Version) had a Law vs. Chaos theme, which I thought worked well
Planescape also dealt a lot with alignment, but I was not too happy with that
Eberron tried hard to subvert the “X has Y alignment” trope (maybe that’s why I liked it that much)
and there is also this Order of the Stick comic strip 