Will there be any more Secondary quests added in the future?

I think a really nice way of incorporating more lore into the games would be to add more secondary quests. The only ones I know of are Kha vs Rengar and Ashe vs Lissandra. Are there any more that I'm unaware of? And is Riot planning on adding more over time? I think it's really cool and would be a great way to promote more interaction between champs in the game. Like... Shen vs Zed or Kayle vs Morgana or something.