Most of the plugins that are used on EMC is custom coded by Aikar. Some of the non-custom plugins might include WorldEdit, and maybe a couple other really basic ones, but all the major features are custom.
As nick said, most are custom-coded for a unique experience. It also prevents people from copying the Empire and creating another server.
What nick said, just a bit curious though; why do you want to know what plugins and more specifically what versions of those plugins are used on EMC?
We use Bukkit/Spigot as our "core" but then Aikar customises it from there. All our plugins, except for World Edit and Mob Disguise (there might be a few more) are pretty much our own.
Of you did /? Instead of /help last July, You could view the default Bukkit help page. This showed a few plugins: -Empire (custom) -Multiverse -Votifier -Mob disguise That is all.
Half of the plugins used here are proprietary.. Like the one program that the mods use.. Square, I think I have heard it called.
Ok I was just curious u guys are really quick to respond. Why do I want to know, because I am playing on the server and I want to know what they use