Unfortunately many of these resources are only on Facebook, but there are a few that are generally available.
The Calontiri Wiki has a running page of general plague related resources, including Arts & Sciences resources:
Calontir.org is maintaining a calendar with only classes and presentations.:
Sir Richard DeBleys has posted several videos for constructing and playing Roman and Norse games:
THL Konstantia has posted a scribal tutorial
Mistress Giraude had shared her online classes on waxed linen and fabric buttons.