Dave: Good idea! Here's the list so far. I've had a few suggestions, so I'll be adding on to it over on my site here:
netraptor.org/blog/2012/08/christian-book-tropesTV Tropes doesn’t have a page for Christian books and what their tropes are. So I’ll take it upon myself to collect and list them. This is a work in progress, so if you know of a trope that wasn’t listed here, mention it in a comment and I’ll add it!
Angels. Winged musclemen in white robes who fly around with fiery swords, beating down demons. See This Present Darkness. Occasionally an angel will appear as a smiling young man in a white shirt who mysteriously helps the hero or dispenses advice, then vanishes. This is sometimes confusing, because the Christ-figure does the same thing.
The Antichrist. According to Revelation, this is some dude who gets possessed by Satan and becomes the One World Leader. At first he’s good, then he turns bad and starts chopping off heads (of Christians). The ultimate big bad, most Christian books wind up trying to prevent his rising or fight him when he comes. See Left Behind.
Armor of God. This is a physical suit of armor that represents the one in Ephesians–the Helmet of Salvation, the Belt of Truth, and so on. The Sword of the Spirit and the Shield of Faith are usually the most important parts. Commonly seen in post-apocalyptic stories.
The Bad Girl. This is the harlot/tramp/sleeper who exists only to tempt the Hero from his path of righteousness. She only cares about her own pleasure. We’re treated to graphic descriptions of her entire body except her breasts. She usually works for the Antichrist.
The Bible. This is called anything but the Bible. The Book of Light, the Holy Book, the Holy Writings, the Sacred Scriptures. But it’s always the Bible and grants either obscure knowledge or superpowers. Expect clumsily-reworded Bible verses.
Breasts. No woman has these. We might be told that she has some nice “assets”, or that she wore a shirt that showed off her chest. But breasts, as we know them, do not exist. Perhaps women in Christian fiction have udders instead.
The Chosen One. This is a kid, or a guy, who goes on a quest to find the lost artifacts, or the birthright, or the sage, or something, that will help him defeat the Big Bad. See Antichrist.
Christ-figure. There is always one of these. He might be a man in a white robe, or he might be a lion or some other sacred animal. He shows up to give the Hero advice, help the Hero when the Hero has reached his lowest point, or in rare cases, actually do something interesting like swing the battle in the good guys’ favor. In other words, the Christ-figure is a literal deus ex machina.
Death. An unpleasant way for the hero and supporting cast to go hang out with the Christ-figure.
Demons. Insidious beings of pure evil. They appear as either patches of living darkness (see the Vashta Nerada) or as scaly lizard-like beings that breathe out sulfur fumes through long fangs. They can also appear only as a whisper in the hero’s ear telling him what a failure he is. Demons can only be slain by angels and occasionally good Dragons. Occasionally the most devout Chosen One can exorcise them.
Dragons. Most dragons are evil because they represent Satan. Some dragons, however, swing too far the other direction and are just dinosaurs with spikes and sometimes wings. Sometimes, you might meet a dragon that is the traditional fantasy type, breathes fire and has wings. But these are hard to find.
God. Generally a caricature of the Christian God, God is a distant deity who sits in heaven and allows bad things to happen to people to make them come to a better relationship with Him. Sometimes God answers prayers or resurrects someone, or heals a wound at a crucial moment. There will usually be a conversion scene where the Chosen One, guided by the Christ-figure, will come to believe in God. Then the Chosen One will get all kinds of Divine Power and beat down the bad guys with it. God is a Deus ex machina.
Heaven. A glowy gold place with lots of light and people who have already crossed over. The hero’s murdered parents/girlfriend/grandparents/best friend are always shown hanging out here, waiting for the hero to encounter Death and join the party.
Magic. There are only two kinds of magic: Holy and Demonic. Because all magic comes from God or Satan. There is no neutral magic, and thus no neutral magical practitioners, even in high fantasy worlds with otherwise standard fantasy rules. Good magic is only used for healing and defense, making everyone either a Paladin or a Cleric. Black magic is used for mind control, summoning demons, and other, far more interesting things.
Magic can also come from Science. Science magic is basically a superpower, like increased magnetism, or super-developed brain lobes to allow telekinesis or telepathy. This kind of magic squeaks past the Occult-radar because it’s more like Spiderman. If Science Did It, then Christians like it.
Nephilim. These are half-human, half-fallen-angel people. There are no aliens, elves, mermaids, dwarves, or any other fantasy race. There are only Nephilim. They can be tall and handsome with pointy ears, or tall and ugly, or tall with big round eyes like aliens. They can be any combination of man and animal (man + horse, man + goat, man + fish). The Rephaim and the Anakim are almost never mentioned.
The Pure Girl. This girl is the Right Choice for the Chosen One. She’s kind, helpful, supportive, and never thinks about sex. She is the Proverbs 31 Woman. If the hero is not saved, the Pure Girl will show him the error of his sinful ways and guide him to repentance.
Satan. The original mustache-twirling villain, always out to take over the world. Satan is always behind every bad thing happening, no matter how fantastic the world.
Sex. This is only allowed if it’s part of a character’s backstory and involves rape or some kind of abuse. Sometimes, depending on the publisher, the abuse can be very graphic. This is so the heroine can be Saved by God later in the book, and learn to love the Chosen One. Love scenes between two married people are never as graphic as the abuse scenes.
Villains. Often the villain is the most likeable character in the whole book. He may be a misguided rogue, waiting for the Christ-figure to show him the error of his ways.
Or he is a psychopath, possessed by Satan or a demon, bent entirely on destruction.
But I would encourage you to follow whatever creative impulse leads you to more like this. 