For those looking to avoid the headaches of dealing with K-1’s on your taxes, here is a short list of ETFs that require the filing of one (there are about 120 securities I have found that generate them). In addition to many of the energy related closed-end funds and private equity groups (like KKR, Blackstone, Icahn) here are the ETFs/ETNs:
iShares GSCI (GSG)
Macroshares Oil (DCR, UCR)
Powershares DB (DBC, DBV, DBA, DBB, DBE, DGL, DBO, DBP, DBS, UDN, UUP)
United States (UNG, USO, USL, UGA, UHN)