Horde Breaker requires the DM to help you. It only works when foes are adjacent to each other, which there rarely is a reason to be.
Colossus Slayer is the most useful, and it is 1d8 damage per turn usually.
Giant Killer is melee only, requires large foes, but is otherwise good. Except, of course, large foes tend to have reach greater than 5'. So it only works if you do the work to hug them.
7th level still sucks with 2 of them. They are all ribbons, not real features. "Immune to fear" is a feature, "advantage against fear" isn't.
11th suffers from too small an area of effect. Whirlwind should let you move up to 30' and attack all creatures who are within 5' of you during this move. Volley needs more than 10' radius. Few Hunters will be great at both of these, so picking both doesn't help much.
15th grants T2 abilities in T3, or an attack redirect.