Kuan-Xi's Guide to Sorcerers

Water

• Shen Gao - The Municipal Sorcerer in the Dragon's Throne
• Aoki Tadako - Weather sorcerer, super Shrouded Isle patriot, not fond of Dragon Army
• Ni Junxian - Elemental Braid
• Yun Ling - Master water sorcerer who works for the Port of the City of Light
• Okura Yosai - The Firelord's guy
• Great Wave Tseng - City of Light
• Ho Kuan-Xi
• Cao Caihong - the Green Duke's water sorcerer, met during Grata,

Earth

• Eternal Redoubt - Elemental Braid
• Stoneback Cho
• Huan Ken - of the Winter Academy
• Tsu Fa - Dragon Army earth mover

Fire

• Lady Suzuki - Kuan-Xi's mother
• Yuwen Fire-Eye
• Zhantai Yuwen Fire-Eye's apprentice
• Ming I aka Wu Wangmu
• Dorga - Fire sorcerer ghost from the Forest of Chin encountered in Ghost Hunters
• Qili Hu - from Yang Shen-Ji and the Goblet of Fire
• The Elemental Braid had a fire sorcerer in Fruit Fight, but I couldn't find the name.
• Inspector Di
• Kusuhara Romi - the Shrouded Isle Regent is said to be a fire sorcerer
• Dishi Delun - The Yellow Duke's fire sorcerer, from Grata

Metal

• Master Bai aka Bai-Jiao of the White Lotus
• Hsu Verity - Elemental Braid
• Renilo - Hsu Verity's apprentice, met in The Price of Good Fortune
• Yang Shen-Ji
• Ezokin - Moneymancy
• Orefinder Liren - from Yang Shen-Ji and the Goblet of Fire

Wood

• Ebon Brush - from Yang Shen-Ji and the Goblet of Fire, Jia-Jia is her daughter, deceased
• Sasaki
• Autumn Rose Nameomancy
• Cartogramancer deceased
• Mu the Mad - met in Amateur Necromancy

Notes and other sorcerers

• Hao Hento - ritualist for the Upward Line (no element listed in log)
• Jia-Jia - Shen-Ji's daughter, pictomancer(what element is that?)
• Sa Zhenren - the only sorcerer known to use lightning (under consideration)
• The Purple Duke's mage, a swamp sorcerer (water/wood)

Note that the Firelord has one of each kind of sorcerer at his court, but we only know one of their names.