So TOS is the odd man out when it comes to continuity, having come before the other series. And the framework established by the TNG-DS9-Voyager-Enterprise era, with its four quadrants, mostly peer alien powers, and other motifs common to that era. One main example I can think of is the timeframe. While TNG/VOY/DS9 is set in the late 24th century, TOS’s timeframe is never made explicitly clear, however in the Squire of Gothos it is stated to be “900 years” after Napoleon or something to that effect. Obviously this contradicts later Trek and established canon. But what other examples of TOS contradicting other Trek can everyone think of? Both lore, style/aesthetics, tropes and motifs and so on. Klingons and Romulans are portrayed generally different, with Klingons more space barbarians or soviets and the romulans as generally honorable but also cunning space romans(hence the name). As opposed to the latter portrayals of a more samurai/Viking honor obsessed portrayal of the Klingons with the Romulans being sneaky and devious. In theory, if you ignored all later Trek you could build off of TOS and have a very different Trekverse with psionic humans, earth like worlds that somehow emerge naturally, a different portrayal of Romulans and Klingons, and it being set in the 28th/29th centuries. But thoughts, examples, ruminations?