OOF there would be a few! i dont know if i have an absolute favourite, but ill list a few from some of my most played games:
1. world of warcraft - sylvaina (sylvanas windrunner x jaina proudmoore)
2. genshin impact - scarakazu (scaramouche x kazuha), diluven (diluc x venti), kamisatocest (ayato x ayaka). i also have a few rarepairs for this game: dilufischl (diluc x fischl), yaezou (yae miko x heizou), yeming (yelan x gaming). the list could go on honestly, i have A LOT of ships in this game.
3. dead by daylight - kable (kate denson x sable ward), ghostleon (ghostface x leon s kennedy)
4. resident evil franchise - leshley (leon x ashley), metaltango (jack krauser x leon), serennedy (luis sera x leon), webecca (wesker x rebecca), star agents poly (jill x chris x rebecca)
5. valorant - reyjoy (reyna x killjoy), cliso (clove x iso), chiper (chamber x viper), deadfear (deadlock x fade)

i might have forgotten some or not added them, but these are some of my all time faves !