Fanfic Recommendations meet Abbott and Costello

[Mamorien]

Second, despairing as yet another timeline goes horribly wrong, Homura wanders into Karakura and meets some strange people interested in this cat/rabbit thing pulling girls souls out of their bodies.

https://www.fanfiction.net/s/11116656/1/...s-Infinity

Seconding this one.  There have been a few other Bleach/PMMM crosses, but this one stands out for how well the two settings mesh, often in unexpected ways.  The author has worked hard, and it shows.

Story is currently on the second time loop (of 54), with the first having ended in true PMMM fashion.

Thirding, for the reasons given, and as an opportunity to boost Smoke and Mirrorless Flowers, one fan's attempt to anticipate Chapter Einundsiebzig that ended up wildly AU but IMO worthy of inclusion alongside the official version. Not only does it include a reference to Wing Bind from Burn the Witch, it has Kyoko Sakura appreciating Orihime's transcendental cuisine.

https://www.fanfiction.net/s/13070680/1/...ss-Flowers

Having just binged this over the last few days while I was sick, I absolutely fourth this. I don't often read PMMM fanfiction (To the Stars being the only one before now that I followed), this one just grabbed me and wouldn't let go.

Addenda over on AO3:
1) As N Approaches Infinity and its side-story collection Polynomial Expansion are available there under the series label Significant Figures:
https://archiveofourown.org/series/912576

2) One astrologia has written two spin-offs:
a) beside you (in time), a thorough emotional workout telling how Homura might, over several loops, come to see Hitsugaya in a different way:
https://archiveofourown.org/works/17677223

b) The Worst Thing Next to Anarchy (Is The Government), set sometime after the possible end of the series, with the puellae of Mitakihara about to graduate from the Shin'oh Academy of the Spiritual Arts and take up assignments with the 13 Court Guard Squads. The first of a promised 17 chapters went up the same day as AN→∞ 76:
https://archiveofourown.org/works/176937...s/41735564

Also, Polynomial Expansion is available at the Pit of Voles, if that's your jam (the main thing I like better about it is one-click chapter jumping):
https://www.fanfiction.net/s/12792869/1/...-Expansion