Snark aside, the Halo novels can probably be enjoyed without knowledge of the games. I say "probably" though because I could say the same of numerous pieces of such fiction, and often such fiction is what keeps my interest in the setting without ever purchasing the games they're based on. But overall, they'd probably be to your taste. Quite a few are fleshed out enough to stand on their own, quite a few have links to one another, and while there's absolute stinkers IMO (e.g. Cryptum and Primordium), there's absolute gems as well (e.g. The Fall of Reach and The Thursday War). Overall, probably worth a look