Cardassians in TOS would be a thrilling sight, what with the interdynamics of Klingon subterfuge and stealthiness back then likely to make them potential allies or keep their respect (these Klingons were the kind that TNG's Romulans became, in sending a spy in the Elasian wedding party to sabotage the Enterprise to explode without even firing a shot until the sabotage was discovered and they had to do things the old fashioned way back in Elaan of Troyius).
Intriguingly enough, Star Trek 25th Anniversary has dialogue referencing the Ferengi in the first mission, but only if Kirk chooses Choice 3 when first awakening the Nauian (the alien remarks that the Ferengi aren't the only traders in the universe, inferring they had at least one venture near ancient Pollux V before the Nauians entered suspended animation until 2269).
Intriguingly enough, Star Trek 25th Anniversary has dialogue referencing the Ferengi in the first mission, but only if Kirk chooses Choice 3 when first awakening the Nauian (the alien remarks that the Ferengi aren't the only traders in the universe, inferring they had at least one venture near ancient Pollux V before the Nauians entered suspended animation until 2269).
