Top Ten Strongest Sternritters in Bleach
This is a list of the strongest Sternritter from Bleach. It's based on their current feats, and how they matched up with the Soul Reapers. (NOTE: There are heavy spoilers ahead within the descriptions of each of the characters, for anyone who is not completely up to date with the manga as of chapter 667.)
At full power, he has access to Yhwach's Almighty but it's severely limited. He can also redirect misfortune and fortune which is already unfair. It's like D4C Love Train from JoJo except it also damages the opponent as well. Needless to say, it's broken. Uryu just happened to have the perfect ability to counter him and even then, it wasn't enough. Like Gerard, it took Yhwach's stealing his power to finally bring him down.
Haschwalth is Ywach's right hand man which definitely counts for something. He is sternritter "B", although the complete extent of his powers is unknown. Ywach upon meeting him, says that Haschwalth is his other half, which could mean that he possesses similar abilities. He too has the "Almighty" although it can only be activated when Ywach is asleep, although he does not have full control of the power. He defeated Bazz- B quite easily and then proceeded to kill him.

He's the leader of the Elite Sternritters who were on the highest end of the Vandenreich Food Chain. He's only behind Uryu and Haschwalth in ranks. His power is absolutely nuts. He can effectively pierce anything as his ability renders durability useless and he can effectively make himself invincible while using this power. Physical attacks and even kido will just go right through him. His vollstandig takes this to an entirely new level and even if, IF he ends up dying, he'll just come back with a stronger divine form. The only way to beat him is to use his own powers against by reflecting it and Nanao just happened to have the weapon for it. Against anyone else though, it's basically game over for them the moment he activates his full powers.
He was Sternritter "X" for "The X-Axis". Barro was powerful enough to take on Shunsui, who was even pushed to use his bankai. When activated, his ability allows him to make it so that when he fires his gun, everything between the target and the muzzle is pierced. All of his enhanced abilities due to the Vollstandg make hime even more powerful. He is defeated and killed by Nanao Ise after pulling a draw against Shunsui.

Askin is Sternritter "D" for "Death Dealing". His ability allows him to calculate the level of lethality it would take something to kill, and change that amount at will, for example, if he consumes blood, he can change its lethality dosage, which makes it fatal to his opponent. With the other Wandenreich, he defeated the Royal Guard. He also defeated Yoruichi, until finally being killed by Kisuke Urahara who was even released his Bankai, which allowed him to create a path for Arrancar Grimmjow, who then killed Askin.
The deathdealing is very Op, and can easily kill most foes by increasing the lethality of blood.

He is the leader of the Sternritter which is why he automatically gets this spot. His letter is "A" for "Almighty", which allows him to see from the present moment, into the far future. Any power he "knows" becomes his ally through this power. Ywach defeats the Royal Guard without breaking a sweat and breaks into the Royal Palace soon afterwards. He then proceeds to absorb the Soul King. All of these feats, especially the latter, probably put him near or at a god- like level. He also stole Yamamoto's bankai and killed the Captain General.
Even without all the power ups he got, he himself specified that no other Sternrittern could use Yamamoto's Bankai but him. That's kinda implying he himself is indeed above any other Sternritterns.
That and the power to kill/take away the power of the Sternritterns just by wishing it. Should be more than enough reason to as for why he is the strongest Quincy.
That said. Almighty is nothing to laugh at. In itself, possess more than enough power to obliterate any opponent in his own universe by simply looking them funny.

His immortality is only second to Aizen's. Because he's part of the Soul King, he doesn't age and his power is like Goku's Zenkai boost on steroids. Not only does killing him or injuring him just make him stronger, but he even gets bigger and to make things even more absurd, his speed and everything else go up at the same rate which is physically impossible. It's so overpowered that Toshiro just ends up calling him a monster that defies reason. And I haven't even mentioned his SWORD. His Sword is a manifesation of the metaphysical concept of people's "hope." If his sword gets chipped by an opponent, the opponent gets damaged as well at a disproportionate rate. So if you chip off like a cm of the sword, you get a HUGE slash across the chest. It's so unfair that even he tries to refrain from using it because it would be too cruel for his opponents much like how Lille Barro tries to hold back by not using his left eye.
He's essentially immortal. Any and all damage done to him he just converts additional strength. He got sliced in half and just stitched himself together. He had his head chopped off and just came back with additional armor.
He is currently fighting and holding his own against the combined forces of Bankai Kenpachi, Toushiro and Byakuya. Gerard's letter is "M" for "The Miracle". Any damage he takes, can be converted into physical size increases, which enhance his strength and durability.

He's a reality warper and on paper, his power basically lets him do anything he wants. The only reason why he lost was because he was so caught up with playing with his food that he ended up getting dangerously cocky. He's so powerful that Askin, one of the Elite Guards, was scared of him and even Haschwalth was panicking the moment he saw him drop a meteor. It's even mentioned that the rest of the Sternritter were too scared to bear their fangs on him. Although it's non-canon, a light novel actually said that Gremmy is part of the Soul King much like how Pernida, Gerard and Mimihagi were.
He had the power to imagine anything, but there is a limit, in that if he imagines himself to be as strong as his opponent, his body may not be able to contain that amount of power. On the other hand, almost every other Sternritter is afraid of him, and he grievously injures Kenpachi, but is defeated. Since he doesn't last very long, his list of feats is short, but they include: Summoning a meteorite large enough to destroy the entire Soul Society, and staying more or less on par with Kenpachi (post training + new shikai).
The most OP power in manga history. It's unknown if with is imagination powers, he can just imagine someone dead and *poof* they're dead. If so, no one can beat him. What is known is that the more clones of him he produces, the greater his power is. He can summon hundreds of firearms, survive in the vacuum of space, and create a giant metorite.
The overly confident kid has one of the most powerful skills ever in history of manga although the way he use it is different, playing with his enemy first then severely wounding them then because of his overly confident attitude he thought he can defeat anyone underestimating them that's why he died because he thought he can match everyones power. But overall he's a beast in battle

Like Ywach, he also has the Epithet of "A", but it's unknown if he possesses the "Almighty" or a different ability. Ywach also claims that Uryu has the power to surpass him. This is why he has the third spot, but he doesn't have any feats to back up.
His ''Antithesis'' ability is pretty useful, if only he was made stronger without it, he'd be formidable enough to be scary

Mayuri might be the only one able to kill him. Conventional attacks do nothing. His intelligence grows based off everything his nerves touch. It took unlimited regeneration to kill him.
It was a part of the elite sternritter group arranged by Ywach. Pernida held its own against Mayuri and also gave Yoruichi a challenging fight. Pernida grievously injured Kenpachi (post training).

Can make everything explode like nothing
The closest Bleach got to a DBZ character
She would have been very formidable if she used her abilities in a creative way

Overpowered and defeated Hitsugaya. His letter is "H" for "The Heat". He did have an elemental advantage against Toushiro though, and was also defeated by Haschwalth quite easily.

Strongest uchiha indeed, he awakened his byakugan after eating the devil fruit mera mera no mi, and he trained harder so that he can unlock his super perfect cell form just to join the sternritter

He was able to defeat Byakuya with medium difficulty and overpowered Renji as well. Nodt also held his own against post-Royal Guard Rukia, but was killed by her later on in their battle.
She is immensely strong enough to increase her physical capabilities.
Of course the "Thunderbolt" would get a spot with that electricity she will SHOCK everyone with her Thunder power. She defeated kenpachi with other sternritter females, fight Ichigo and having a hard time againts him.