I said Favored Foe sucks because you have to split damage between 3 targets to increase total damage.
Which makes sense. FF replaces a noncombat feature. So it has to be valued as such.
Whether it sucks or not depends on what else you can add to the attack action to increase the amount of damage. As Favored Foe is not the only feature that doesn't cost you an action to use.
A Bugbear's Surprise Attack doesn't cost an action, but it does come with a conditional in that it only works if you hit a creature that has not taken a turn yet in the current combat. So, any opponent who is behind a Bugbear Ranger in the initiative timeline is fair game.
A Gloom Stalker's Dread Ambusher trait doesn't cost an action. It's also conditional in that only works at the start of your first turn of each combat and if you decide to make an attack action. But if you do, you get an additional attack and were to hit an opponent, you do an additional 1d8 damage. This additional attack works well once you reach 5th level and gain Extra Attack from your class.
A Rogue's Sneak Attack, likewise, doesn't cost an action just as long as you meet its' conditions (finesse or ranged weapons with advantage, or when your target is flanked by a teammate)
I am sure that there are other race/class traits other than these ones that don't require an action to use so long as the conditions are met. And they can be met if you think creatively, your character has these particular race/class traits and a moment of opportunity comes along.
Which noncombat feature is being replaced by Favored Foe? AFAIK, the only feature that Favored Foe replaces is the 2014 Favored Enemy trait (which is highly situational).
