The Mythic Odysseys of Theros book lists, for each of the gods, the domains most associated to them, as well as a list of suggested classes.
Here is an example for Athreos (p. 38):
Athreos’s Champions
Alignment: Usually lawful, often evil
Suggested Classes: Cleric, monk, rogue, wizard
Suggested Cleric Domains: Death, Grave (described in Xanathar’s Guide to Everything)
Suggested Backgrounds: Hermit, sage, sailor, urchin
Obviously, this isn't an exhaustive list.
However, I haven't found a similar mapping for the warlock pacts or patrons. Does any information on this exist in the book (that I've missed)? If not, is such information available elsewhere?
Otherwise, how can I best determine which gods/monsters/entities make sense for each warlock pact and patron?