In this photo, Jones can be seen playing a Elka Capri combo organ (also sold under the Panther 300 name).

Goldwasser used an Elka Panther 300 heavily on the MGMT album Congratulations. In this photo from an MGMT practice session, Ben's red Elka Panther can be seen on the far left.

Sound on Sound's article about Congratulations discusses Ben's use of the organ:

Meanwhile, the highly idiosyncratic sound of 'Congratulations' was being created using an array of new musical toys discovered by the band. Chief amongst these was the Elka Panther organ that features throughout. "We found it on Craigslist in LA and got it for about $400,” says Goldwasser. "It needed a little work on it. The vibrato knob's broken but everything else works great. I got really obsessed with transistor organ sounds early on in the recording process. For me it was the most psychedelic sound of the moment. I just love how jarring it is and how cartoony it is. It's this weird reddish orange colour and it's set up differently from some of the other organs. For each register, there's different stops that have a different tone. But then it has a volume knob for the whole stop, so you can set up a tone on one and then you can mix it. It's really musical and you can get so many tones from it really easily.”

Bown can be seen here playing an Elka Capri 300 (same as Panther 300) with the English pop group The Herd on Top Of The Pops TV in 1967.

Don Preston can be seen in this photo using an Elka Panther 300 combo organ, which he used early on in his time with the Mothers of Invention (most notably on Absolutely Free).

In this photo, Rowberry can be seen playing a Elka Panther 300 organ with the Animals on Top of the Pops in 1965. Rowberry usually played a Vox Continental with the Animals, and his use of the Panther was likely very short lived. A photo from a different televison show can be seen here.

Presser Gábor played a Elka Panther 300 in the Hungarian rock band Omega. An additional photo can be seen here, and a pretty sweet organ solo can be found on YouTube here.

Carolyn Wood played a Elka Panther 300 combo organ during the Brooklyn Bridge’s performance of “Worst That Could Happen” on the Ed Sullivan Show in 1968. Video here.

Rick Stelma can be seen here behind an Elka Panther 300. The picture comes from the back cover of a reissued single by Dr. Spec's Optical Illusion.

Maurice Montez posed behind an Elka Panther on the cover of her 1966 instrumental album The Groovy Organ Goes Romantic. A footnote on the bottom left of the front cover reads "PANTHER Jazz Organ Courtesy of Merson/Unicard." (I'm not sure what Merson was, but I think Unicard is a misspelling of "Unicord.")