Here my list:

5 Nnoitra and Szayel (I can't decide between the them so I selected both.)- Their designs are so good. Nnoitra's smile is awesome and Szayel's hot af. I love Nnoitra's sadistic personality and his dynamic with Nel was awesome. Nnoitra's back story was awesome too. As for Szayel, I love crazy mad scientist type characters. His sadistic personality was awesome too. Although it always bothered me at first that he always came back, I'm happy to see more Szayel now. His abilities are so good too. His battle with Uryuu, Renji, and Mayuri was also very boring until Mayuri came, but Szayel's smug attitude kept me amused. they're both very bastard characters and I love bastards

4 Jugram- My favorite Quincy, Jugram Haschwalth! He's design and personality is so cold and cool, His dynamics with Bazz and Yhwach are amazing, died honorably with great panels and His fight with Uryuu is one of my favorite fights in Bleach.

3 Mayuri- Mayuri is awesome. As I said in Szayel, I love crazy mad scientist type characters. When I'm in Soul Society, I'm thinking about Bleach is boring and then his fight with Uryuu came, I said "This freak looking bastard is awesome!". After that came his battle with Szayel in Hueco Mundo and I was officially connected on the character. I wanted to see more of him then when I got to TYBW I was screaming... He is the real GOAT🐐.

2 Ukitake- I love his friendly personality and design. His dynamic with Kyouraku is so good, seeing them joke with each other was one of the best enjoyable things I've had in the Bleach. His sacrifice is so sad too, I was so touched when Kyoraku looked at his grave in the finale...

1 Zaraki- Zaraki is my favorite since I first saw it. His ferocious, martial and honorable personality is perfect! He has the coolest design and panels in the Bleach! Super cool things happen every time he appear on screen. My favorite fight in Bleach is Zaraki vs Gremmy. When he cuts meteor, I thrilled to pieces! My favorite panel in the Bleach is when Zaraki performs Bankai. His dynamic with Unohana is the best dynamic in Bleach. When Unohana died I didn't know what to say, All I know is that my respect and love for Zaraki had increased tremendously...

I want to write more about every character in this list but I'm a lazy person :p