When I first think of jazz songs in anime, Cowboy Bebop immediately comes to mind. However there are many catchy jazzy anime opening/endings out there. Here is a quick list of a few of my favorites, and of course I'll start us out with a little Cowboy Bebop to get us going.
Cowboy Bebop - Opening "Tank"
Samurai Champloo - Ending "Shiki No Uta"
JUJUTSU KAISEN - Ending "Lost in Paradise feat. AKLO"
Kakegurui - Opening - "Deal with the devil"
Baccano - Opening "Guns & Roses"
JoJo's Bizarre Adventure - Opening 2 - "Bloody Stream"
Space Dandy - Opening - US / Toonami Version
Lupin the Third - Live Action - Anime Opening
Deal with the Devil is best opening for me
Bloody Stream is definitely my favourite opening ever but Tank is amazing.
Tank is amazing, I never skip the opening credits any time I watch Cowboy Bebop. I was lucky enough to see Yoko Kanno live at Otakon in 2013. (Wasted half a day of the con on line to get tickets, but worth it!).
I haven't watched Kakegurui since it aired and I totally forgot how jazzy its OP was.
Deal with the Devil and Lost in Paradise are so good!