Kamen Rider official time-line https://www.kamen-rider-official.com/history That had main series, cross overs, movies, specials, etc. And they place in the time-line and production. Mostly old considering the current events of the show, but Dragonalos and Gaiard was the first 2 Chemy in all the world(that was explained in the episode 26) but in the notes of the episode they explain that they immense power was the reason that they create the other X-Level Chemy and gave birth to the concept of Level Number in Chemie's. https://www.kamen-rider-official.com/gotchard/27/