Copious thanks to paw broon and to movielover for the recent spate of Schoolgirl Picture Libraries. I really enjoy these stories, especially the secret society ones. The artwork is uniformly good. It's interesting that despite differing styles from artist to artist, there is an overall look to the schoolgirl stories. Notably there's a conscious effort to keep the drawings "light," even in adventure stories, using lots of pen hatching and staying away from shadows. Alex Toth's issue must have come as something of a shock. Judging by that sample page he stuck to his bold chiaroscuro style.
I do wish someone had an artist index to these comics. I can spot a few styles but I don't know any names.