River Song is basically a female Jack Harkness. Flirting with everyone, travelling through time, you never know where you are with her right now. I love her but there are lots that think it's overdone and too much and complicated the more she was brought back.

Madam Vastra and Jenny are great! They have been in a few more episodes before Deep Breath. Here is also a fun short clip:

https://www.youtube.com/watch?v=Rirju6is4Sw&list=PLxyHNwLICTy3y7jUrnNHEkhnR8ir96AP6