I have updated several pages in the Drug Discovery Resources.

Ester and Amide Bioisosteres https://www.cambridgemedchemconsulting.com/resources/bioisoteres/ester_bioisosteres.html

Cysteine Protease inhibitors https://www.cambridgemedchemconsulting.com/resources/hitidentification/focus/cysteineprotease_inhibitors.html

Covalent Inhibitors https://www.cambridgemedchemconsulting.com/resources/lead_identification/covalent.html.