Here’s a few extensions I’ve come across recently
FilterTool – This is how Revit’s filter tool should work.
From their site: You're able to filter not only the categories of your selection but also the types. Your selection is level-based. Additionally, you can save pre-defined Filters, so whenever you need a recurring selection, just open a saved Filter selection in our FilterTool.
ideate explorer – Same as above except even more powerful. I need this and I need it now. Considering they are about the same price if you get the office version of filtertool, I think this is the right choice.
Revit Excel Import – Converts excel files to dxf so you can import them into Revit as a link. It’s not very ‘BIM’ that’s for sure, but there are times I could’ve have used this.
Metal Wood Framer – I know of many people that have been looking for this, it automatically creates wood or metal stud framing from your Revit walls
BIMreview – THE way to maintain standards in Revit.
I’ve only tried BIMreview so far because we are currently on a purchasing freeze. Stinkin economy is preventing me from having any fun.