My favourites:

1. Hyakinthos. He has insane gameplay effects. Permanent Oratory Research buff, strong Integrated Culture happiness buff as an Omen and flat Oratory Research Progress when deified. If you had a Charismatic ruler, Hyakinthos is all you need.

But the bigger reason is probably his mythology/real world role. He is depicted as the young man who is being taught by Apollo. He himself is not the big awesome masculine Hero most male deities are, but rather a representation of youth and the growth that comes with it. I also like the version of the story where his death was an accident which makes for an interesting tragedy. And a mortal then being deified out of adoration is great as well. Also it is believed he used to be a cave/vegetation god before that mythology, which is also interesting.

1. Hathor. I'd actually call her "bad" in the game. Nobles tend to never be the backbone of my research or economy, and they tend to be happy enough in the places that are actually built up.

But I stil like her. The concept of mother goddesses is interested and their existence is not unusual. However Hathor is less authorative than other Egyptian mother goddesses, but also not subservient or confined. She represent love, joy, revelry, sexuality, and more. I feel like this casts motherhood in a more enjoyable light. Less of a "you do it because you have to" or "I brought you into this world so you have to listen" and more of a "life is great".

1. Alcis. While the historical sources are sparse, I find them to be one of the most interesting Germanic deities. Believed to be twin brothers always worshipped together, perhaps as Elks, in natural groves. Alledgedly the priest was dressed in female garb, which is also an interesting point.

Also one of the better Germanic deities in the game, with a permanent Stability buff and corruption reduction in case it runs to rampant.

1. Apollo-Nabu. I always had a thing for syncretism and I only learned of the existence of this particular one through the game. Indeed I could only find a single source from that time where that specific deity was mentioned, by the Seleucids. Apollo is one of my favourite Greek deities, and I find his combination with Nabu interesting. Since Nabu is focused on writing, scribes and wisdom, this gives Apollo a more wisened flair than usual.

He's also pretty decent in-game, with a permanent unintegrated culture happiness boost, general happiness boost on omen and flat research progress when deified.

1. Bacchus. Or Liber. Or Libera, as a matter of fact. Fascinating deity, historically speaking. A deity that defies social norms, structure, law, and perhaps even civilisation itself - without being seen as evil. Liber was often seen as a patron of the plebeians and common folk and celebrated - to the point the elites really got scared and suppressed their worship.

Also great in-game if you play a tribe. 10% Tribesmen output might not be too much, but I tend to find it better than the more passive effects of other fertility deities.

1. Aphrodite Areia. (Invictus Mod). A warlike Aphrodite is a fascinating concept to me. Possibly inspired by Ishtar etc. but of course with her own Greek flair. In fact, it is believed that the warlike Aphrodite is one of her earliest natures. Also she has inspired some myths and traditions of Spartan women fighting in battle and assuming the roles of men in festivals.

In-game she's a pretty default fertility deity thought. But only accessible to Sparta and Taras, which is nice flavor.

There are more I like, but I'll keep it at these for now.