At the moment the third party restaurants haven't been added to the 2014 dining plan list so the first post in this thread lists the non-Disney owned restaurants plus the ones that do not participate in the dining plan:
http://www.disboards.com/showthread.php?t=3172886
Edited to add: Looks like the third party restaurants have been added to the DDP brochure so Nala will probably update the thread I linked. Here's a list of the third party restaurants she has listed on the thread:
LIST OF THIRD PARTY RESTAURANTS
All restaurants at Downtown Disney except Food Quest (counter service inside Disney Quest; requires Disney Quest admission)
All restaurants in the following Epcot World Showcase pavilions: Mexico, China, Italy, Japan, Morocco, France
All restaurants at the Coronado Springs Resort except the pool snack bar
Yak & Yeti (Animal Kingdom)
Big River Grill (Boardwalk)
The following restaurants do NOT accept the dining plan at all:
All restaurants at Shades of Green
All restaurants at Swan and Dolphin
Victoria & Albert's (accepts the Platinum package plan only)
Lounges (in the parks: Tune Inn, Tutto Gusto, Rose & Crown Pub (not the restaurant; the pub is separate), La Cava del Tequila)