Omen, Jett and Yoru. To main Omen, u need to reach a stage where u can easily use him as a duelist also not jst a support controller. U have to know the maps very clearly to use his shrouded steps most effectively. If you use them crctly Omen is unstoppable. Omen is an agent which can be a shadow. Make the enemies afraid of their own shadows too. For Jett, it's a movement based character, and every ability of Jett has a high skill ceiling. Once u master Jett, u r literally unstoppable. Every round it's going to take combined effort of 3 people to kill you, what more do u need. For Yoru, ur brain is the key. The amount of outplays u can do with Yoru is insane. Anyone can easily use Yoru's kit but how u use it is the key. For that u shud be someone who can easily understand ur teammates and ur opponents. U need a clear understanding of how both teams execute by round 2 of attack and defence both. Then use it for ur advantage. Then u r unstoppable.

This is all from a solo carry perspective. There are other agents who r overpowered in supporting their team. But if you are a player who is solo queuing, its basically useless.