Endless Quest books. But I'd hardly call them novels, per se. Most of them were fun reads, though.
The first D&D-based novel I read was Artifact of Evil, by Gary Gygax himself. I still have my brother's old and ragged copy. I was probably 10 or 11, and was a little shocked and amused at some of the foul language used by the villains in the story: the infamous dwarf Lord Obmi and hid insane elf accomplice Keak.
But I liked Gord's quest across the continent with his companions to hunt for the Artifact of Evil. It starts with the end of a massive siege in the Pomarj and ends up in the Vesve forest. Adventurers come and go (and even perish) from Gord's group.
On the way they passed through the Village of Hommlet, met Melf the Elf, and even the Archmage Tenster. Its starts with the end of a massive siege in the Pomarj and ends up in the Vesve forest. Adventurers come and go (and even perish) from Gord's group. My favorite character was actually Gellor the half-elf bard.
It's a good meat-and-potatoes book with its simple plot, though at first I didn't understand what the Artifact of Evil would do (it'd be many years before I'd get the chance to read Saga of the Old City, the first book in the series--which is also a good read).
Its also the best book of the series, though I say this without having read all of the succeeding books. I read Sea of Death but couldn't get through Come Endless Darkness. The writing style had changed, was less vibrant, some parts were a chore to get though. No doubt Gygax's ousting from TSR affected the execution of these books beyond just having to change many of the names when he published the rest under New Infinities.
Still. Artifact the Evil is a high point and worth reading.