Hello! Happy to see someone who wants to participate in Anzu Week :DD and I'd love to help you in any way that I can! Although like what I always tell people, I always have a hard time recommending stories involving Anzu since she's spread across lots of stories >.> I feel bad for writing recommendations that might accidentally have biased content hagsdjhgsd

ES! Main Story (if you can find the novel, even better!!) and SS arc (Summer Live, Revenge Match, SS) is a must to see her starting points (and descent to overworking....) ! Anzu is also hilarious in the events where she produces big events like Tabanata Festival, Orihime and Hikoboshi, Sweet Halloween, Dark Night Halloween, Quarrel Festival (the only ones I can remember at the top of my head i'm so sorry). Aquarium, Boutique, First Shrine Visit, Hospital Visit, School Trip, Class Live, and EP:Link feel like must-reads too!
Reading stories involving Anzu and Kaoru /Madara's relationship feels important too since it's gives insight to into her as a person as well.

For Anzu's !! School life and Producer life, you should go read Spring Bed, Main Story 1.5s (Seven Bridges, High and Low, Black Jack, Poltergeist, Graduation), a bit of SS (Satellite, and all the Gatekeeper & Anzu bits in every story bc they are so funny + her importance to the idols), 2x2, Xday, Evil Telephone. Plus Feature Scouts too since she's involved in almost all of them

If it'll help, I also recommend reading @/trystofstar's amazing anzu doc for a fast overview of her character and ES! arc: https://docs.google.com/document/d/1EEzPBYf4vx6q0J-US8EHJkPECSQQUsaemz-xjIBb69Y/edit?usp=sharing

.>)
(<.<

but since I know not a lot of people look at my retrospring, you can have this as a preview for a thing I've been working on: it's a story breakdown based on anzu's activities in each story! Right now it only has EnGirls and a simple guide for ES stories (but just bolds for recs or categorizations) since that part is still under construction in a separate doc, but I hope it helps! I'm planning to make the EnGirls part public once the Paradise 10th Anniversary arrives, but it has a bit of EnStars too so it might help (and some shipping guides too) (but also I may actually delete the EnStars part in the future if I feel like not including anything from those stories until all the breakdowns are complete) : https://docs.google.com/document/d/1XG6YQ0zgq7FY9wpm5OLrQYJ3LpM5oVy_Y97JNcbOzGc/edit?usp=sharing
(haha but don't share it around please it's still incomplete so it'd be embarrassing)