Ah. The most prevalent one I recall was tied into the chat system, for general chat, shop chat, and I think a couple other channels. No autoloot or the other standard fare. They also customized the Warp skill, with @memo 1, @memo 2, and so on; this was so you could save warp points to a particular spot on the list, rather than constantly shuffling down your list and losing the last warp. Think @who was also incorporated...All utilitarian stuff, anyway.
Not sure how that ties into Aegis/eAthena outright, but it should be said that that server was unique in that aspect. I can't recall what iteration was used, but it was recoded almost from the ground up. Took a couple weeks pre-launch debugging skills and such. My stint of dev work was mostly related to DB management, beta testing, and authoring quests for our coder.
