While reading a PhD dissertation, I was pleasantly surprised to learn about the Lexicon Iconographicum Mythologiae Classicae (“Iconographic Lexicon of Classical Mythology”; a.k.a. LIMC; 1981-2009). It is a 16-volume encyclopedia of ancient Greek, Roman, and Etruscan art showcasing historical examples for each deity. The books cover gods alphabetically, starting with “Atherion-Eros” and ending with “Thespiades-Zodiacus.”

(Image found here)

The tomes are presented in pairs of eight matched volumes, the first comprising articles describing the art and the second with pictures.

I would LOVE to get physical copies, but they are very expensive. Thankfully, there are options. First, black and white PDFs of the full series are available on Internet Archive. (See below for a screenshot of a couple of pages (of many) focusing on Heracles.)

https://archive.org/details/limc_20210516/Lexicon%20Iconographicum%20Mythologiae%20Classicae/LIMC%20I-1/

And second, there is a searchable website.

https://app.dasch.swiss/project/BRwvcfLLT72IN-fXzQkrdQ/data

Admittedly, though, I would rather flip through pages of the physical books.