The Wiki's page is not updated with all of them, it still has the old Pixelmon's info since it's missing more of those Pokemon like Karrablast and Shelmet, plus more Pokemon of those mentioned in there can be found in the wild, like Kingdra and Politoed.
But, even in some of those Pokemon's main wiki pages it is not mentioned if they can be found in the wild or not, like in Kingdra's page it is not mentioned that it can spawn anywhere although it can be found in Deep Ocean biomes with Super Rod fishing. Unlike in Politoed's page it is mentioned normally.