A good investment is also getting guild banners for your toons. The best one increases XP from killing monsters for guild members within 100 yards by 15%. Having a few of these in your group and cycling through them can result in a decent chunk of extra XP for your group, especially when doing big AOE pulls (for example monkey runs).

Then there's of course Elixir of Ancient Knowledge (at least I've not heard of it being removed). Hard to aquire, but on quiet realms or by camping multiple realms at a time, you might just get lucky to get some of these. I did get about 4 of these just casually checking for the mob every now and then and they do make a huge difference.