For help with the logistics of remote work see: Tools for Working Remotely
General training
LinkedIn Learning (formerly known as Lynda.com)
Training videos on a wide variety of topics, including various Office products (such as Access and Excel)
Box.com documentation from IT@Cornell
Cataloging-related training
Fundamentals of Library of Congress Classification
Presentations, Exercises, and Supporting Documents from RDA Toolkit Workshop: A Crash Course (January 2020)
Library of Congress Subject Headings
LC created this extensive subject heading training for their overseas offices and continues to update them regularly
Watching these all is a long-term commitment!
IFLA LRM (Library Reference Model)
Modules from the PCC Standing Committee on Training (2020)