How I first found The Emotion Thesaurus: A Writer’s Guide to Character Expression by Angela Ackerman and Becca Puglisi (2012), I have no idea, but you can see that both the cat and I find it enormously useful, if for slightly different reasons.
The ability to identify and describe body language and facial expressions is critical in conveying emotion on the page. The authors list dozens of emotions, from adoration to worry, briefly define them, then set out physical signals, internal sensations, mental responses, and other key indicators. They also include a section on avoiding common problems, such as too much telling and cliches, and tips such as finding the root emotion, using the setting, and using visceral or instinctive reactions.
I use the lists as a starting point, thinking about a particular character, their personality, gender, how they use their body, how controlled or demonstrative they are, the intensity of the situation. You are the ultimate authority on your characters, but the authors’ lists will get the ideas moving. I’ve annotated my copy, listing additional emotions, adding observations of my own, and interleafing other resources. The authors have also written books on character traits, setting, and more. I see from their website, Writers Helping Writers, that they’ve put out a new edition of the Emotion Thesaurus. Maybe the cat will get me a copy for Christmas.