Since many series have a 91st episode, here are other notable installments if you were looking for a different show:

Goro's passionate, individualistic style clashes with Keene's disciplined, system-oriented approach.

Features the intense battle where Yusuke's demonic aura begins to manifest during the Sensui arc.

Episode 91 features a discussion on dating shows for women aged 40 to 60.

Season 5, Episode 3 (91 overall) titled "Clash! Class A vs. Class B!" kicks off the Joint Training Arc.