Tips for an increased multiplier.
Here you go, a full list of items with a multiplier by LPN http://forum.ea.com/eaforum/posts/list/10335203.page
Forum Discussion
As much as I hate them - build Springfield Heights buildings. Don't worry about upgrading them, just build them. Outside of spending literal boatloads of donuts on multiplier items, the heights buildings will be the quickest way for a lower level player to boost their xp multipliers.
