In otaku/fan culture they have always called their favorites oshi (推し), it say in google that comes from the verb osu, which means "to push" or "to recommend", it's like the idea that you must support your favorite, can be idol, character, celebrity and so on. It's used in Japan, I may be incorrect on this, but with the increase in vtubers who use the "oshi" concept, it seems to me that it became popular with western fans
As far I know, bias is used for kpop groups, but the concept is similar. Having your favorite, being biased towards someone.
Husbando/Waifu has always existed in otaku culture, and is used with the character you see as a romantical partner / kind your favorite.
* I may be wrong in certain parts