Huh, ironically I felt that Yui Kamio was really Ranma-like before the recent shift but more in terms of it's story. Art-wise Saiyuki is more like that era (also because kid heroes), though I remember Takahashi having a softer style.
Top five, only one per series:
1. Large-Scale-Invasion from WorldTrigger (with a huge distance to the rest... for me this arc redefined how large-scope shonen battle arcs can work)
2. The 4th Drift, including the Neo Amakusa Stuff in Psyren
3. Kamino Hideout Raid in My Hero Academia
4. Chunin Exams in Naruto, especially the first half
5. That flashback Arc in the last part of Rurouni Kenshin
Honorable mentions and series duplicates:
Stagiare in FoodWars, Old Piccolo Saga in Dragonball, Sasuke Retrieval + Hidan and Kakuzu Arc in Naruto, Stain Arc and Endeavor/Hawks Arc in HeroAca, Rank Wars in WorldTrigger (maybe not a traditional "arc", but whatever).