Paul Farquhar
Legend
I've tried googling this sort of information. There is rarely enough for me to feel satisfied that I "get" the deity and the temple structures around them.
Sure, I can easily find that Corellon is the god of the elves, rules over war, magic, beauty, and singing, and once put put Gruumsh's eye in a battle. However, I've got no idea what his priests wear, are there holy days like commemorating the battle with Gruumsh? What do they do on that day? What is an appropriate offering to Corellon? What do his temples look like? Are there multiple levels of hierarchy in the temple?
All that information is stuff that gets made up, and since I grew up in the Bible Belt it ends up looking like a lot of different flavors of Christian because when I'm on the spot and thinking "What does the church look like" I think of... well Churches.
Counter Anecdote: I've never been in a 5e game that didn't include at least one cleric at some point. From that perspective they are far more popular than Fighters and Wizards.
Personally, I would really like some of this sort of information to be made available, but I wonder since it would be too massive for a book if it could be something added to DnD Beyond or something. It would just be incredibly useful to have a compilation of all these deities and detailed suggestions for how the Temple structures work.
This is where polytheism is being confused with Christianity. There is no "uniform" for a priest of Corellon, holy days depend on locality, there are no standardised rituals, and very little in the way of hierarchy. Each temple would have an autonomous high priest, and he/she would have a few acolytes. Appropriate offerings are "anything the god likes" so in the case of Corellon, singing, mostly (and all temples need cash for maintenance).
It's not a case of "making information available" since this information does not exist in the first place. Go ahead and make it up, because nothing is going to be published to contradict you.