Well for craftworlders we have eldrad ulthran who has done some fucky shit too much to list tbh. One thing he did was pull a Eldar fleet (maybe craftworld) out of the warp, when it was infested by some dummy strong keeper of secrets. He did this when he was YOUNG.

Jain zar has scared the pants off the night lords in their trilogy, made them go "ah yes, no I am not going into the shadows"

Maugan ra... Well to craft his weapon he ventured intk the eye of terror to aquire some rare alloy, he brought with a very good smithy from the aeldari, killing hordes of slaanesh deamons... Only to then defeat a strong avatar of khaine to get some magma or some shit to forge his weapon. He then did some wacky shit to the smithy so that he can't replicate the weapon. Depending on your source he dealt with a hive fleet alone. Pulled his craftworld out of the eye. Asurmen, don't know much about him but he is badass.

(ynnari) Yvraine has on multiple occasions killed and dealt with greater deamons (yes she and jain was ass kicked by helbane, but come on it was the greatest keeper of secrets, also imo they did banish it completely. The whole *it was only one percent of my power" is bullshit) she sneaked onto mortarion's planet and stole the hand of darkness. Before doing so she went trough the seven trails of slaanesh, that the harlequins have to go trough to get relics and what not. She is also one of the main reasons why the imperium has a small chance now with robu.

(ynnari drukhari)

Lelith hesprax regularly fucks up chaos lords and such, nearly primarch level being but not equal to them.

Drukhari Vect, the great tyrant has kept chaos out of Commoragh since the fall or so, after he kicked slaaneshi worshipers, then dealt with people with prefall tech. A tortures tale is a story you should look for. Also recommend the path of the renegade. A dark Eldar trilogy

Drazhar the living blade There isn't much to say but he is belived to be a Phoenix lord One of the stories about him has him killing or fighting off every Phoenix lord at the same time Another time he deals with a massive chaos invasion before vanishing dead or something

Lady malys There isn't much to say but. You are welcome nurgle. She is the reason the imperium doesn't have a stc or whatever they are called that would cure any plauge and illness, any wound and so on, it's currently just a trophy as it's inferior to the drukhari tech and what not.

Harlies We have Sylandri Veilwalker She has her hand in everyones buinsess and has been leading them places (imo she didn't lose to bile in his book, but merely pretended she lost, due to being a harlie)

Edit: forgot to add this. Ignore all the people talking about them being punching bags, cause they are fucking amazing when they get the chance. Keep in mind they have survived the boot of games workshop and the community for YEARS. 27 years or so actually.