The Kzinti get an tiny offhand mention in Ishmael, as Kirk walks past a couple in a Starbase corridor.
Yep, and briefly mentioned as the
K'zinti in "Battlestations!".
KZIN mentioned ("From Sputnik to Warp Drive", in "Star Trek [The Enterprise Logs] Volume 4" and "Worlds of the Federation").
KZIN homeworld was shown on star charts of the United Federation of Planets and its environs ("Star Trek Maps", rendered as the
Kz'nti and
Kznti Patriarchy; episode "TNG: Conspiracy"). An area indicates location of
The Patriarchy ("Star Trek Star Charts").
KZIN COUNCILOR of "The Time Trap" and "Star Trek Log Four" - Bear-like, prototype Kzin member of the ELYSIAN COUNCIL. Named as a
Berikazin ("The Time Trap" novelization in "Star Trek Log Four"). Cleverly not mentioned by name ("S.C.E.: Where Time Stands Still", eBook).
Kznti marker buoy featured ("Star Trek Maps").
Fth-Captain and crew featured (LA Times syndicated comic strip storyline, "The Wristwatch Plantation".
Note: That storyline was intended to have been novelized by Sharman DiVono with Larry Niven, but it did not proceed beyond proposal stage.
Race rewritten as the M'dok Hegemony, another antagonistic felinoid race ("TNG: The Captains' Honor"). Race rewritten as the Mirak Star League, yet another antagonistic felinoid race ("Starfleet Command" game series, based on "Star Fleet Battles", which featured the KZIN, without Niven's or Paramount's grace).
The triple-breasted female felinoid dancer (in "Star Trek V: The Final Frontier") was referred to in backstage information as a "Kzinretti".
Although we never see representatives of the Tzenkethi Coalition ("DS9: The Adversary", TV), some fans (wrongly) assumed that this now-alligned race, with whom the Federation fought two wars ("DS9: Paradise Lost"), was intended to be the Kzinti, due to the near-anagram of the name. A Tzenkethi settlement is located on M'kemas III ("DS9: The Adversary"). Garek claims to have been a spy on Tzenketh ("DS9: By Inferno's Light", TV). Tzenkethi male described as a "feliform" biped ("DS9: Infinite Bureaucracy" short story in "Strange New Worlds VII").
In 2006, the screenwriter Robert Hewitt Wolfe, who coined the term "Tzenkethi" for DS9 recalled, "I basically made them up. And yeah, I named them. But I can't remember if I was making a purposeful homage to Niven or not. If I had to guess, I suspect I did my usual and combined a couple things. Probably Kzinti and Tsankth. But when I picture them in my head, they weren't big cat people. I thought of them as more like the Hakazit."
(The Tsankth are from "RuneQuest" and "HeroQuest". The Hakazit are from Jack L Chalker's "Well World" novels, and are described inconsistently as either: three-metre tall Tyrannosaurus Rexes with powerfully strong arms; or large mosquitoes.)
There is also no connection between the Xindi ("Star Trek: Enterprise", TV) and the Kzinti, despite both fighting wars with Earth.