Masterplan 8.5 and earlier had a compendium import feature, though it was only for monsters. A lot of the older libraries are still floating around but they'd have to be imported with the old version before you can use them with the newer version.
Once upon a time there was also a scraped version of the compendium but this was years ago. I don't know if anyone scraped a newer version (and subsequently shared it). Theoretically I suppose any web scraper would do, but for obvious reasons you probably shouldn't share it.