Heritage Foundation has a list. It has about 2000 instances over the last 20 years: https://www.heritage.org/voterfraud

Not a lot.

That's an average of what, less than 1 per election? Even focused on a single election, it would not be sufficient to swing Bush vs Gore in Florida.

It has 1290. 1290 is not about 2000.

Followed the link on an oregon one.

“At the time of the election, (Robbins) was suffering from kidney infections which impacted his cognition,” said Oregon Department of Justice spokeswoman Kristina Edmunson. “He does not remember voting two ballots, but acknowledges that he did and is extremely remorseful.”

I think 2000 instances counts as "many".

Regardless, the main point still applies. That's only the fraud we know about. The amount of fraud we don't know about that people are getting away with is an unbounded number that we literally can't even estimate given the nature of the crime. Again, this isn't identity theft or robbery where there is a clear victim to tell you "hey a crime has been committed against me" even if you never catch the perp. In the case of voter fraud, there will never be a smoking gun if you don't catch them first.

Regardless, it's fairly obvious that less ID verification / policies that result in less of an audit trail make fraud easier to execute without getting caught.