Whose calligraphy to practice depends on your calligraphy style
If you are a relaxed person, you can practice Yan Zhenqing’s Yan Qin Li Stele, Duobao Pagoda Stele, and Nephew Memorial Manuscript (block letters);
If your characters are restrained, you can practice Ouyang Xun’s Jiucheng Palace Liquan Inscription (block letters);
If your characters are delicate and slender, you can practice Liu Gongquan’s Mysteries Pagoda Stele, Shence Army Stele (block letters);
If your calligraphy style is cautious, you can practice Zhang Xuan’s epitaph, Zhang Menglong Stele (Wei Stele)
There is also Lingfei, which I don’t know about Sutra, my calligraphy teacher recommended it to me (block regular script)
If you are good at it, you can practice Xing Kai script. Wang Xizhi’s Lanting Preface, Shenlong facsimile and Dingwu facsimile are all fine.
I really couldn’t make up my mind, so I practiced Yan Zhenqing’s calligraphy, because many of Yan Zhenqing’s calligraphy were left behind. However, Yan Zhenqing’s calligraphy is not easy to overdo, while European style is easy to overdo.
The above are all published by Cultural Relics Publishing House. I don’t know where they are sold. I buy them all from my calligraphy teacher, but I think you can search them online
I That’s all I know, I hope it helps!