Just a handful of things that were helpful to me, or that I developed with other allies, while working at Etsy.
Start here: THE BEST PDF on allll this stuff at a high level.
Recommended Reading for Allies by Toria Gibbs and Ian Malpass (Code as Craft)
Impact of diversity work, positive and negative, from the book of Gender & Work (PDF)
How to be a sponsor to members of underrepresented groups
Tips for managers of marginalized people
Slide decks for managers and staff engineers on how to be sponsors, with Venkat Mahalingam
Study: Women ask for feedback as often as men—but are less likely to receive it (PDF, look at page 14)
Research: Vague Feedback Is Holding Women Back
How to give more effective feedback
The full story of that engmgr photo and their allyship
Difficult conversations manager interview roleplay description with Seth Walker
Different ways we've recognized engineers
Research that Daniel Schauenberg and I did on "returnships"
Thank your local ally: Etsyans' favorite baked goods