I think you're asking only Bonafide Document stuffs. In my case, this is wot i sent within packages & made copy of each items to take with me for interview. It was successful.

- Picture of photos with husband & wife ( I copied 6 picture from actual ceremony-nepali style & 2 from court marriage...2 snaps each page on MS word with time & decription underneath as caption style...total 4 MS word pages printed in color from Office Depot...The interview lady was impressed !!! )

- Joint bank account - Opened bank account couple of months ago...put some money there & printed 2 statements online myself

- Lease paper from apartment - first page of the lease papaer where you both sign...& highlight with marker @ signature

- Utility Bills - I called my energy supplier 1 month earlier to put my wife name on it.....&  they did...later i printed my bill online which showed both of our name..& i highlighted with marker again

That was it in my case & it was more than enough.....Having said that, they pay attention for couples...rather than documents. If you guys  donot have big age difference & both from same country....trust me they wont even look at your documents...My interview was 4 min long.

Good Luck

*** I went in detail cuz while i was preparing documents, i needed help for managing documents in proper way before sending rather than what documents were needed....Hope this helps you lil bit & GOOD LUCK " !!!