Addendum to the already given excellent answers. It appears to not only be Mr. Craig.
Source (Note: The source contains spoilers)
...it was well-known that SIMON PEGG had filmed a cameo in The Force Awakens for Abrams after starring for the director-producer’s Mission: Impossible and Star Trek reboots. Pegg can be seen and heard under layers of Crolute flesh as Unkar Plutt, the Jakku junk dealer who trades rations for spare parts and sends a few thugs to steal BB-8 from Daisy Ridley’s Rey.
Fans also have [Simon] Pegg to thank for first spilling the beans on The Force Awakens’ funniest guest appearance. “I wasn’t a stormtrooper. DANIEL CRAIG, he was a stormtrooper,” he blabbed in May, seemingly confirming rumors that Star Wars fan Craig would be cameoing in Episode VII.
Alec Guinness, Ewan McGregor
The Obi-Wan line came courtesy of not one, but two Kenobis: ALEC GUINNESS, whose archival utterance of the word “afraid” was cleverly edited into Abrams’ dream delivery of the name ‘Rey,’ and his prequel counterpart EWAN MCGREGOR, who recorded the rest.
“So when you hear Obi-Wan talk to Rey it is both Alec Guinness and Ewan McGregor doing the voice,” said Abrams.
Here he’s Admiral Statura, a member of the rebel force set on taking down the First Order.
In The Force Awakens, he gets to live a geek dream as Snap Wexley, a Resistance fighter from a piloting family who’s part of Poe Dameron’s Starkiller Base attack squad.
Yayan Runian, Iko Ywais, Cecep A. Rahman
YAYAN RUHIAN—aka Mad Dog from The Raid—gets to taunt Solo as Kanjaklub leader Tasu Leech, while IKO UWAIS sports some otherworldly coiffure as the whimsically-named Razoo Quin-Fee. The pair served double duty on The Force Awakens as credited fight choreographers on said Millennium Falcon sequence, which also boasts Raid 2 standout CECEP A. RAHMAN.
Dowager Lady Shackleton of Downton Abbey tending to Chewbacca and his ego as Dr. Kalonia—or as the stage and screen veteran is known IRL, DAME HARRIET WALTER. (Fun fact: Walter is also the niece of another Star Wars icon, Sir Christopher Lee—Count Dooku himself.)
... cameos from British stars and Star Wars fam, including Carrie Fisher’s own daughter, BILLIE LOURD. The young actress shares the screen with her mother a few times at Resistance headquarters playing Lieutenant Connix, an officer in Leia’s new rebel army.
Abrams also cast his own dad, Emmy nominated producer GERRY ABRAMS, as a character named Count Cypress—and named Oscar Isaac’s X-wing pilot after his onetime personal assistant, Morgan Dameron, whose Star Wars name is, appropriately enough, Commodore Meta.
Bill Hader, Ben Schwartz
Meanwhile, those adorable bleeps and blurps coming out of BB-8? They come courtesy of Saturday Night Live’s BILL HADER and BEN SCHWARTZ
Thomas Brodie-Sangster, Jessica Henwick, Miltos Yerolemou, mark Stanley, Max Von Sydow
Over on the Dark Side, the fascist-like First Order is populated with sinister-sounding Brits. The Maze Runner’s THOMAS BRODIE-SANGSTER turns in a one-liner as an officer of the First Order, one of several Game of Thrones stars to pop up in The Force Awakens alongside Gwendoline Christie’s Chrome Trooper Captain Phasma. (See also: JESSICA HENWICK, Season 5 and 6’s Nymeria Sand, who battles in an X-wing as one of the Resistance’s female pilots; MILTOS YEROLEMOU, who played GoT’s Syrio Forel and also gave Eddie Redmayne his sexual reassignment surgery this awards season in The Danish Girl; MARK STANLEY, who played Night’s Watch ranger Grenn but is hard to spot as an unnamed Kylo Ren disciple; and MAX VON SYDOW, who’s joining GoT as one of Season 6’s big name additions.)
Michael Giacchino, Nigel Godrich, Gustavo Dudamel, Lin-Manuel Miranda
Tom Kane, Meredith Salenger, Catherine Taber, Sam Witwer, Matt Lanter, James Arnold Taber, and director Dave Filoni
And then there are the fun, random cameos that you’d never know existed otherwise. Longtime Abrams composer MICHAEL GIACCHINO dons a stormtrooper costume as a First Order soldier named FN-3181, while Radiohead recording producer NIGEL GODRICH plays stormtooper FN-9330.
Abrams had even more musical surprises up his sleeve. The LA Philharmonic’s own dashing music director GUSTAVO DUDAMEL came in to guest-conduct portions of John Williams’ Force Awakens score in secrecy. And those cantina-esque ditties blaring in Maz Kanata’s space pirate bar come courtesy of Hamilton composer-star and expert freestyler LIN-MANUEL MIRANDA, who sang alongside Abrams in Huttese on jams titled “Jabba Flow” and “Dobra Doompa.”
Meanwhile, The Force Awakens also played host to the voice cast of its popular animated prequel series Star Wars: The Clone Wars. Listen closely for the voice work of Clone Wars stars Tom Kane, Meredith Salenger (yes, Natty Gann herself), Catherine Taber, Sam Witwer, Matt Lanter, James Arnold Taber, and director Dave Filoni.
…it will make a gazillion bucks and be the highest-grossing movie of all time because it is a direct doorway to our childhood.”