Hi Nikki,
One of CASL's many Let's Library professional learning sessions last year focused on Manga. The amazing Sara Smith led it. The good news is that CASL members can log into ctcasl.org > PD & Resources > members only content and you'll be able to access the recording, slides, and title list (which includes titles for elementary through high school). As a high school librarian, I recently consulted the title list and found just what I needed! See screenshot below:
(Note: above is a screenshot. Log into your CASL account to access the links.)
Valerie DiLorenzo
CASL President