Xingyi Baguazhang:
A Hybrid Martial Art
Zhang Zhankui, courtesy name Zhao Dong (张兆东 1859-1940), was a prominent martial artist in Northern China and was particularly influential in Tianjin. He first learned a style of Northern Chinese Long Fist called Mizongyi Quan. He learned Hebei Xingyiquan from Liu Qilan (刘奇兰, 1819–1889) and trained regularly with his sworn brother Li Cunyi (李存义, 1847–1921) who learned Baguazhang under Dong Haichuan (董海川, 1804-1882) and primarily trained with Cheng Tinghua (程庭华, 1848–1900).
When Zhang was a younger man he gained a reputation as a bounty hunter. A large man, Zhang is thought to have been nearly 7 feet tall and was quite imposing with a large torso. He eventually learned Baguazhang from Cheng, under Dong's name. Unlike Cheng, who primarily practiced Shuaijiao, or Yin Fu who was a Luohan master, Zhang used the Xingyiquan body method as his base and created Xingyi Baguazhang. His arts of Baguazhang and Xingyiquan both changed as he aged - it's reported that his choreography became less extended and the Mizong influence lessened.

Zhang
Zhao Dong
Jiang Rong Qiao
A Martial Arts Genius, Prolific Author
Mizong Mastery
Jiang Rong Qiao (姜容樵 1891-1974) was a master of Mizong Luohan Quan, he learned from his uncle Jiang Detai. Later he learned with the the famous Chen Yushan who was thought to have revived the style.
Hebei Xingyiquan
Jiang Rong Qiao first trained with Li Cunyi before becoming Zhang Zhaodong's disciple. While Jiang was exceptionally talented and capable, his Xingyi lacked a distinctive flavor and did not become its own substyle. Jiang was renowned for his prowess with the sword and other weapons.

Prolific Author
Unlike many martial artists in the past, Jiang was quite literate and published 28 books in his life. He served as the head of curriculum development at the Central Guoshu Institute from 1932-1944 when the Japanese invasion occurred. He then retired and taught middle school afterward.
Baguazhang Reformulated
Jiang trained a number of Chinese martial arts. His Old 8 Palms Baguazhang is a reformulation of Zhang's Xingyi Baguazhang. While Jiang was an indoor student of Zhang's for over 20 years, he was not a constistent student and was also heavily influenced by Li Cunyi's Dragon Baguazhang. Later, Jiang also developed a New 8 Palms set.

Tri Internal Martial Arts - Henry Look's Gong Fu
An Architect's System of Gong Fu
Henry Look was a Chinese American with roots in Shanghai. His family was highly educated and he pursued an education and career in architecture after serving in World War II. Kuo Lien-Ying was Look's first teacher in the arts of Baguazhang, Taijiquan, and Xingyiquan. Kuo was a martial arts genius in Muslim Long Fist as well as the Chinese internal martial arts who studied Yiquan directly with Wang Xiangzhai. Kuo's Cheng Baguazhang came from Chang Xinzhai and learned Yin Fu's Baguazhang from the legendary Ma Gui. While he did not get much of the Baguazhang from Kuo, he trained enough to have many questions.
Han Xing Yuan was primarily known for his Xingyiquan and Yiquan skills but had extensive training in over a dozen martial arts. His father Yousan was a disciple of Zhang Zhaodong and both Xing Yuan and his older brother Xing Qiao were trained in multiple arts prior to learning Yiquan. Zhang was the creator of the art of Xingyi Baguazhang - a hybrid martial art that integrated the Xingyi body method and Baguazhang tactics. Wang Xiangzhai was brought to Tianjin and Zhang and Jiang exchanged with him. Han Xing Yuan was more than capable in teaching Bagua and taught Henry Look Jiang's Old 8 Palms. Dug Corpolongo mentioned that Yu Pengxi also taught Look some small portion of the Baguazhang he knew but their training together focused on fajin.