The 6120 was designed by Gretsch and endorsed by Chet, himself. This guitar was the original "Country Gentleman" and in a well-documented presentation of Chet's gear, Premier Guitar stated this:

"All aesthetic extravagances on the 6120 were eliminated on the Country Gentleman, which came along in 1959. Chet’s personal edition is surely one of the most beautiful electric guitars ever built, even if the f-holes are decals."

"...this is the guitar heard on most of those dazzling records"

She confessed her undying love for the ’58 Gretsch 6120 she acquired in 1985 and detailed her stage and studio rigs.

"The Cochrans moved in 1953 to Bell Gardens, Calif., where Eddie immersed himself in his increasingly adept guitar playing. In January 1955, at age 16, he dropped out of high school to become a professional musician. Also that year, Cochran acquired the guitar he was most closely associated with, a Gretsch 6120 Chet Atkins hollow-body. It was a brand-new instrument (serial number 16942) that he bought from the Bell Gardens Music Center with financial help from his parents. Cochran was very particular about his guitar sound, and he soon modified his 6120 by replacing the DeArmond DynaSonic™ neck pickup with a black Gibson® P-90, which had a warmer, jazzier sound that Cochran liked."

This guitar was used by Ritchie in the Movie Johnny B. Goode

Ángel Parra frequently uses the Gretsch 6120 in his concerts, as shown in the user-uploaded photo from Fmicassets.

John Flansburgh is pictured with a Gretsch 6120 guitar in this promotional photo.

Mentioned semi-anecdotally in this Gibson article.

I guess we can reasonably say, therefore, that the legendary rock and roll rig isn’t just one set-up, but an evolution of pairings: the music set forth from big-bodied Gibson archtops like those played by both Bill Haley and Comets guitarist Danny Cedrone, or—a couple years later—the Gretsch 6120s Eddie Cochran and Duane Eddy played.

This guitar would later inspire Eddy's signature model, a modified version of the original.

Randy With Dick Clark on Bandstand in 1978 with a green Gretsch 6120. His original 59 orange one was stolen in 1976 at his hotel.

And yes, Petersson also collects standard six-string guitars, which he uses to write and record. Classic American guitars in his set include a 1934 Martin 000-18, a 1960 double-cutaway Gibson Les Paul Junior in TV yellow, a black ’63 Fender Telecaster, an orange ’67 Gretsch 6120, a Gibson Barney Kessel Standard from ’62, a prototype Gibson Super 400 from ’91, a ’59 Rickenbacker 360 Capri, a ’67 Rickenbacker 360/12, and an original black ’57 Gibson J-160E (as played by John Lennon and George Harrison) that he prefers for recording, “Because of the lack of low-end, it fits in the tracks better.” Another favorite acoustic is a 1950s Artur Lang hand-made in Germany.

"Gretsches sit in a different part of the frequency mix than the Fenders or the Gibsons. They carve a different spot, which is why I played so many live." - Zac Brown

Used by Mitch Galbraith (Rhythm Guitar) in it's left-handed format in 'Constucting The Diamond' on YouTube

On some clips filmed from his home during quarantine (such as https://www.youtube.com/watch?v=RchxKfRP2Ww ), Conan O'Brien pans his webcam and you can see his Gretsch 6120.