The most famous running script is Preface to Lanting written by Wang Xizhi, a calligrapher in the Eastern Jin Dynasty. Predecessors described it as "a dragon flying from heaven, a tiger lying in a phoenix" and praised it as "the best running script in the world". In the Tang Dynasty, Yan Zhenqing's "Sacrificing a Nephew" was bold and unconstrained, and the ancients rated it as "the second running script in the world". Su Shi's Huangzhou Cold Food Sticker is called "the third running script in the world".
Pen and calligraphy are similar, just find one that suits you (it looks pleasing to the eye).
I hope it helps you.