There are currently 10 Breath Styles. But there are Trainers that trains people and makes people learn the breath style. There are 9 Breath
<Thunder Breathing> Agatsuma Zenitsu
Zenitsu is located in Rice Field and next to the huge house.
<Beast Breathing> Hashibira Inosuke
Inosuke is located in the huge Forest near the Tanjiro Boss and in the middle of the 6 huge pillar
<Wind Breathing> Shinazugawa Sanemi
Sanemi is located in Minobu Village in middle of the huge house close to the Nichirin blade crafter.
<Insect Breathing> Kocho Shinobu
Shinobu is located in Butterfly Estate and Shinobu will be sitting somewhere surrounded by the bush
<Flame Breathing> Rengoku Kyojuro
Kyojuro is located near Minobu Village hiding behind the huge rock and in between the sharp rocks.
<Mist Breathing> Tokito Muichiro
Muichiro is located behind the Hokkaido Town sitting on the Bench.
<Flower Breathing> Tsuyuri Kanao
Kanao is located in the Butterfly Estate. She will be standing in front of the very small hut Near where the Sakura and the Cuaguesty is.
<Serpent Breathing> Obanai Iguro
He is in the swamp. When you go down and see the 'Male Infected Human', you will also see the very, very high rock. Iguro will be sitting there.
<Love Breathing> Kanroji Mitsuri
She is at the Demon Slayer HQ, inside the big shelter holding her flexible katana.
<Sound Breathing> Tengen Uzui
He is near Muzan. When you see the landmark (pillar), go straight.