Short answer: there isn't one. Even Skyteam has a bigger presence than Oneworld. The UA FC lounge is the nicest but jealously guarded (no access unless you are flying UA in F), otherwise Virgin or the Star lounges. Usually I use the Delta CRC as it is outside of security and has Anchor Steam on tap (but closes at 11 pm). Rather surprising that the brand new International terminal built at a cost of hundreds of millions of dollars (close to a billion including the roadwork) made allowance for such shoddy, poorly constructed and poorly located lounge facilities.