Having been a beta tester back in the day, and being able to "cast spells" as a mage with a dragon before it was revamped to "dragon only" and "dragon abilities" there were a lot of fun things back in the early days.

Server lag for the "resource" computer allowed players to load up their main pack with thousands of units of gathering, but none appeared in the pack. It was a fun race to second guess the game server when it would "catch up" with you and ground you with the inventory overload. Some players that got grounded became "movable silos" for other guild members to come and trade with for raw materials, or if you got grounded next to a machine, you could reap the benefits yourself.

When dryads were introduced as a playable race, The excite emote made the dryad stretch in unbelievable ways, (including certain female body parts) due to the fact the "dragon" emote was accidentally used for dryads. It was a site to see.

Hatchies could not fly, there was no ROP yet. It started at level 50, and is somewhat different today than it was back then. It is a lot easier to get to the ROP quest areas now, and not tromp through level 100+ blighted creatures.

Tier 4 nodes was it... there was no tier 5 or tier 6 until later. There were Steel golems, they disappeared for a while, then recently reappeared.

Housing was in-game, but no one could buy plots yet. They were auctioned off.

Have fun adding to this list!