These are all the US Credit Cards that I am aware of that currently offer any form of lounge access. (Note: Business card versions of some of these also offer lounge access)
Alaska Airlines Visa Platinum Plus - 2 free boardroom passes
https://www2.bankofamerica.com/credi...=VA&ssid_data=
Continental Airlines World Mastercard - 2 free presidents club passes (per year)
http://www.firstusa.com/cgi-bin/webc...rld&page=index
Continental Airlines Presidential Plus Card - annual full presidents club membership
http://www.firstusa.com/cgi-bin/webc...cont&mkid=674L
Delta Reserve Credit Card - access to Delta Crown Room Clubs
https://www201.americanexpress.com/c...=37/21452/b/57
Korean Airlines Visa Signature - 2 free VIP lounge coupons (per year)
http://www.skypassvisa.com/cgi_w/cfm...redirect=nm201
US Airways Visa Signature - 1 free US Airways club pass
http://www.bankofamerica.com/usairwa...gn&referralid=
US Airways Platinum Plus Visa - 1 free US Airways club pass (per year)
http://www.bankofamerica.com/usairwa...at&referralid=
Citi Platinum American Express - Priority Pass access (3 free visits per year then $24 per visit)
https://www.citicards.com/cards/wv/c...o?screenID=927
American Express Platinum - CO,DL,NW,AA lounge access
https://www143.americanexpress.com/c..._c&benefitId=1
Merrill+ - AA or DL lounge membership with $50,000+ annual spend
https://card.ml.com/MLRewardsCenter/...s-Benefits.htm
Diner Club Charge Card - limited international lounges
http://www.dinersclubus.com/dce_cont...airportlounges
Citi Chairman Card - Priority Pass
https://www.citicards.com/cards/wv/c...o?screenID=945
Bank of America Accolades American Express Card - Priority Pass
http://flyertalk.com/forum/showthrea...=702751&page=4
Ameriprise World Elite Mastercard - Priority Pass
http://www.ameriprise.com/amp/indivi...d-elite-mc.asp
You can also see which lounges are available via Priority Pass, American Express (Platinum Charge US), Diners Club, Lounge Pass, and on a paid daily membership on the individual program sites or via this tool
http://rewardsdb.com/lounge1.php