Tokk Tournament

A Tokk Tournament is a tournament where you can battle trainers from previous regions, along with rematching Gym Leaders, held in the Tokk Tournament Hall in Xzyit City. There are 10 types of them.
In each one, 7 people from the list of people you can battle are randomly selected, and you are placed in the first slot in the brackets of the tournament, and the other 7 trainers are placed in the 7 other slots. There is a "trainer index table" that shows which trainer wins against which one, or if it's random, if two NPC trainers are battling.

It also allows you to battle trainers from previous Pokemon regions, including the Gym Leaders from Kanto, and many other regions.

The 10 types of Tokk Tournaments are:

Ubife Gym Leaders (7 of them are selected):

Nni-ottine (the Sout City gym leader)

M (the Kkhaltel City gym leader, Hcio retired)

Hhirik (the Sayyid City gym leader)

Icì (the Zgierz City gym leader, Ihleite started a new gym)

Hxewwaq (the Mqabba City gym leader)

Ijolite (the Hka-U City gym leader)

Jxara (the Zneteri City gym leader)

Kmer (the Xzyit City gym leader)

If you beat the Ubife Gym Leaders tournament and have become Champion, all of the other regions' Gym Leaders tournaments unlock.

Kanto Gym Leaders (7 of them are selected):

Brock, Misty, Lieutenant Surge, Erica, Koga, Sabrina, Blaine, Giovanni

Johto Gym Leaders (7 of them are selected):

Falkner, Bugsy, Whitney, Morty, Chuck, Jasmine, Pryce, Clair

Hoenn Gym Leaders (7 of them are selected):

Roxanne, Brawly, Wattson, Flannery, Norman, Winona, Tate & Liza (considered one person), Wallace, Juan (Wallace and Juan can not be in the same tournament.)

Sinnoh Grm Leaders (7 of them are selected):

Roark, Gardenia, Maylene, Wake, Fantina, Byron, Candice, Volkner

Unova Gym Leaders (7 of them are selected):

Cilan, Chili, Cress, Lenora, Burgh, Elesa, Clay, Skyla, Brycen, Drayden, Iris, Cheren, Roxie, Marlon (All 3 of Cilan, Chili, and Cress can not be in the same tournament, also Lenora and Cheren can't be in the same tournament, Marlon and Cress can't be in the same tournament, and Drayden and Iris can't be in the same tournament.)

Kalos Gym Leaders (7 of them are selected):

Viola, Grant, Korrina, Ramos, Clemont, Valerie, Olympia, Wulfric

Alola Leaders (7 of them are selected):

Ilima, Lana, Mallow, Kiawe, Sophocles, Acerola, Mina, Hala, Olivia, Nanu, Hapu

Galar Gym Leaders (7 of them are selected):

Milo, Nessa, Kabu, Bea, Allister, Opal, Bede, Gordie, Melony, Piers, Marnie, Raihan (Bea and Allister can not be in the same tournament, Opal and Bede can't be in the same tournament, Gordie and Melony can't be in the same tournament, and Piers and Marnie can't be in the same tournament.)

Once you beat all of the Leaders tournaments, and have beaten the Pokemon League a second time, the Champions tournament unlocks.

Champions (7 of them are selected):

Blue, Lance, Steven, Cynthia, Ghetsis, Alder, Iris, Diantha, Kukui, Leon, Trespassers W

Once you beat the Champions tournament 5 times, Red will start appearing in the Champions tournament, always appearing in the last slot. Red's trainer index causes him to win against every other NPC trainer so, if you get to the finals of a tournament that has Red in it, the final battle will always be against Red.