What evidence was found at the Nicole Brown case?

To me the most important evidence in the case of the death of Nicole Brown (and Ron Goldman) were the testimony of witnesses (the pool house tenant and the person he was talking to on the phone, the limo driver, the skycap at the airport), the actions of the defendant before the crime and immediately following; the statements of the defendant regarding his actions of that day; the identity of the blood samples from various locations; and the implausible effort of the defendant to try the gloves on at the trial (I would have difficulty putting my own leather gloves on if I was wearing latex gloves, try it).

The letters that Ms. Brown left in the safe deposit were very chilling, as well as the recordings of her calls to 911; they were examples of a textbook abusive situation and the voice of the victim from the grave. Excellent secondary evidence.

Then the "conspiracy" theory of the defense was very telling also, but you didn't ask about that.