Websites like Ririro offer stories and books categorized by grade level (e.g., 4th Grade/4ème) which are sometimes available for download in bundled formats.

Similar to the Luxley series often shared in downloadable formats, these stories involve characters waking up in alternate realities with limited memories. rar file you've already downloaded? Histoire 4ème - Apps on Google Play

There is a free MMORPG called 4Story that users occasionally search for using similar keywords. Story Concepts for "4EME"