Friends of Monika have found and picked up content Otter left behind, deleting their GitHub account and Google Drive.
These spritepacks are preserved as is, only JSON files have been prettified automatically to make them all look uniform and valid.
Head over to latest release and scroll down to the Assets section. You'll see a bunch of spritepack .zip files.
Download those you are interested in, open folders containing stuff you want
(you should end up in a folder that has game and characters folders), then
drag and drop both folders into the same folder where DDLC.exe file is along
with folders game, log and alike.