You can't get any maps from quests or by buying them in-game that work in the in-game map. You can get some items in-game that are called "maps" but they don't work as in-game maps.
Besides downloading them, you can make your own also. The map windows has a box at the bottom that brings up the tools to create / edit maps. It's not a great tool, but is fast for mapping with the AutoMap function.
There are also tools you can download (mappie the only one coming to mind atm) that you can use out-of-game to view and edit Everquest in-game maps.
Yther ore.