Technically, there are no Old English novels, since the novel form only arose in the 1600s - well into the Modern English era. You should be able to get value out of any classic novels from Jane Austen (early 1800s) onwards. Possible you mean "old English novels" - old novels in English, not novels in Old English.
Can you give an example of the novels you have read that you've spotted strange grammar in?
Student or Learner