Oh boy. This is WAAAY harder. There are so many awesome companions! Yaz, Sarah Jane, Martha Jones, Captain Jack...so many that didn't make my list! But, this is what I have so far:
5. Donna Noble
Yeah, Donna is HILARIOUS. She was such a breather after the gross love stuff with Martha and Rose. It is very tragic how she had to leave the Doctor. She will always be remembered.
4. Ryan Sinclair
I admire Ryan. He has to go through life with his mother dead, his gran dead, and a really bad father. He also has a disorder where it's hard for his brain and hands to click. But he pushes through this and travels with the Doctor. He's AWESOME.
3. Amy Pond
Oh, Pond. Her friendship with the 11th Doctor was unlike anything we had ever seen. And her love for Rory was different than her love for the Doctor, which was interesting to see. Her ending was sad, but at least she got to live out her life with Rory.
2. Rose Tyler
Rose was REALLY cool. In the beginning she was a little...uh...clueless, but after travelling with the Doctor for a while, she became cooler. And better. At everything. Her love for the Doctor was beautiful, and she and the 10th Doctor played off of each other very well. Rose was, I hope, happy with the human Doctor she got to live with.
1. Clara Oswald
It seems like there's no inbetween with Clara Oswald. You either love her or you hate her. I love her. She is the most interesting companion we had. Her downfall was obvious though. She was just too much like the Doctor.
Let me know your favorite companions, and what you think of this list!