Some scholars of theology believe that all the world actually only worships a single pantheon of gods; it's just the names and representations of them that differ, as well as regional importance of one god over another. Others resist that notion, calling each nation's pantheon of gods a unique set, specific to that culture, although cults may migrate from culture to culture from time to time. Be that as it may, these are the gods that have temples in the Mezzovian Sea area, with the (often foreign) names by which they're most commonly known.
Honestly, people in general are better described as "superstitious" rather than "religious." Offerings and invocations are tossed off out of habit, and people have a healthy respect for the ability of a displeased god to give you a really bad day, but they don't often otherwise pay particular respects to them.
The names given (underlined and italicized in the body of the description) are the regional names common to the nearby area; they differ slightly by dialect in other locations, or may have entirely different names in some regions. The way the pantheon works is that no god has "primacy" over another one according to myth. The various gods work in their respective sphere of influence, and their importance varies from region to region. Because I like campaigns set in very lawless, free-wheeling, decadent places, the Black Prince is an important god locally to most campaigns I run, although he's seen differently (and plays a much more minor role) in many other regions.
The Black Prince - The Black Prince was originally a god of bandits, brigands, pirates and outlaws in general. Despite the fact that most countries long ago applied a veneer of legitimacy and civilization, worship of this god is still very common. He's seen as a representation of the more romantic notion of pirates and outlaws, but nobody forgets that piracy and highway brigandry is an inherently nasty business.
He's also adopted a new aspect; most civilized lands now see him as a god representing the nobility, law, civilization itself. I'm sure it says something about society that a divine robber is what they find most representative, but worshippers give this little thought, and his pirate background is often forgotten or even actively surpressed. By superstition, he's rarely named aloud although his name is well known (Grazazat) and is instead usually called the Black Prince, or the Six-fingered Man. His image is common in small statues or icons across the land; he's tall, handsome has six fingers on each hand and has a "crown" of six small horns pushing up through his hair. His icons are always made of obsidian or basalt, or some other black stone, and other images are always painted pure black. Because his description across most of the region is very similar to that of the hamazin, they feel that they are his special children, given preference over all other peoples in the world.
The War God - The god of war is named Bel (hence the expression casus belli). He is seen as a large, powerful figure with a sword in one hand, a whip in the other, and wreathed in flames. His local temple has been the source of some scandal in the past, and a dark god named Abaddon supposedly had his priests infiltrate the temple and poison some of the high ranking priests. These were then discovered and killed; the clergy is therefore relatively young or new to the area; few of the older priests still reside here.
Goddess of Knowledge - A relatively respectable god with a lavish temple is Astaroth, the Great Librarian. It's said that in the Last Days, her library will burn, heralding the end of civilization, but in the meantime, Astaroth is quite proud of her library and encourages her clergy to seek for whatever knowledge they can find. Dark whisperings say that the more forbidden the knowledge, the more highly it's prized, and occasionally scandalous rumors come from this temple, but by and large it is seen as one of the more respectable in the area, and is justly considered a point of pride to its residents. Astaroth herself is depicted as an angelic human with large feathery wings, a serpent in one hand and a book in the other, often seated on a coiled dragon for a throne.
God of Death - Urkas is not much worshipped or revered locally, but since his temple has charge of preparing dead bodies for funerary rites, it remains important nonetheless. Ironically, the priests of Urkas are notorious for trying to escape death---urban myths of the priest of Urkas who turns to dark necromancy are common bogeymen that mothers use to frighten their children. Urkas himself is never pictured out of superstitious fear; nobody knows what he's supposed to look like---or if they do, they're not saying.
God of the Sea - One of the most respected and revered gods near any body of water is Dagon, the Lord of the Sea. Since literally everyone in coastal areas depends on the sea to some degree or another---either for food, livelihood, or at least in the hopes that it won't rise up in a tropical storm and wipe them off the map---Dagon's ceremonies are the most attended of any in those regions, and icons of him appear in almost every single building. He's usually shown as a merman with a flowing beard, but he's also occasionally pictured otherwise; one popular variant is a shark-like creature with grasping tentacles and mouth and eyes similar to that of horrible deep sea hunters.
Goddess of Magic - Abraxas is the Goddes of Magic, and few are the arcane spellcasters who don't at least give her some nominal votive offerings from time to time. Her priests are famous for selling charms that protect the faithful from minor harm and bad luck. Most people agree that they do indeed work, although some decry the practice as charlatanism.
Goddess of Travelers and Roads - Ahrimanes is the ultimate traveler. Most people about to embark on a long journey will stop by the temple district and touch the hem of the robe of her statue. Most cities have a brass statue of her in an important plaza, but temples are few. Clerics and other faithful clean and polish the brass statues daily. They do, in fact, frequently start to lose some of their detail and definition because of the constant polishing.
God of Strength - Bathemoth is a bull-headed god famous for his feats of strength. His temples are small shrines that are simply a roof supported by four pillars with a granite altar in the center.
God of Nature - Yinigu is often seen as a dark god; a representation of nature "red in tooth and claw." Hunters and outdoorsmen worship him, but these are hard and cynical men, usually. He is also heavily worshipped in Kurushat, where he's seen as a god of hyenas and a patron in particular to the kurushi and their allies. In other societies, this is often rejected as a false cult, and Yinigu's chosen messengers are seen as wolves. Which, honestly, doesn't make them any more welcome.
God of Penitance - Not a popular god, but one that you occasionally hear about from those who have had to spend time in prison. Azazel encourages extremely dilligent penitance and flagellations, so his followers are at least easy to spot.
God of the Sun - Moloch is the god of fire and the sun. His worship is more prevalent in tropical, open areas (unsurprisingly) where he is seen as a harsh and demanding master. In more temperate climes, he's more likely to be viewed benevolently, as a bringer of clement weather and bountiful harvests. Southerners shake their heads knowingly, and watch their own crops go sere with Moloch's displeasure.
God of Thieves - While never openly worshipped, Frezur Blue is very commonly given a quick prayer by the land's many less than upstanding citizens. Many invoke his name only to make fun of it, and ask what part of him is blue (usually with a randy joke about his sex life) which causes the priests of Astaroth no end of frustration. They simply roll their eyes, comment that "Blue" in this case is merely a mispelling of his proper name anyway, and although Frezur Blue may seem to be an easy-going god who doesn't mind a few jokes made at his expense, only the truly foolish think that it is wise to upset the god who can take away everything that they own, and even steal their very souls.
Many other gods exist, but these are the ones that are most important and that everyone will know. Many thanks to Green Ronin (Pirates Guide to Freeport and Armies of the Abyss) for many of these concepts.