The Seddie/Creddie Fan War Pairing in Super Sentai
There are some fan wars of pairings in Super Sentai similar to Seddie vs. Creddie. Note that none of these are canon but they do happen...
After Takeru /Red Mask broke up with Ial, there's the argument of Haruka vs. Momoko for Takeru. He does have chemistry with Haruka while with Momoko, it's purely professional. I'd call this the Takeruha vs. Tamako fan wars or if Ial is still on board, the Takeial fan shipping.
Carranger had both Zonette (the official pairing with Kyousuke) vs. the fan pairing of Kyousuke with Natsumi with I would call the Kyosuzette vs. Kyotsumi fan wars. In my own shipping, I prefer the Kyotsumi one.
Then we have the Tamako vs. Takoha fan wars. Some people say Takeru Shiba has better chemistry with Mako, others argue Kotoha. I'm on the Mako boat but I don't mind those who prefer the latter pairing instead since they don't really affect canon. My problem though with Kotoha x Takeru is... it might be just a crazy response to the rumor that Kotaro Tanaka was dating Sayuri Uchida in the past.
There's the Marvelous x Ahim vs. the Marvelous x Luka. I'm in the Marvelous x Luka shipping even if neither is really a canon pairing. I don't find much chemistry in Marvelous x Ahim compared to Marvelous x Luka.