Ok, this is a fair debate. Some thoughts:
"They found them in creeks." I think Trump was referring to the ballots found in ditches in Wisconsin. So, technically inaccurate, but an immaterial inaccuracy. Same goes for the rivers comment.
https://www.fox6now.com/news/wiscon...trays-of-mail-absentee-ballots-found-in-ditch
"They found some with the name Trump—just happened to have the name Trump—just the other day in a wastepaper basket." This is true, though I suppose slightly inaccurate because they were found in a dumpster not a wastepaper basket.
https://www.npr.org/2020/09/24/9166...nce-theyre-investigating-discarded-pa-ballots
"They sent two in a Democrat area. They sent out a thousand ballots. Everybody got two ballots. This is going to be a fraud like you've never seen." I think he means Fairfax, VA.
https://www.nbcwashington.com/news/...ty-voters-received-2-mail-in-ballots/2427435/ And another in Richmond, VA.
https://richmond.com/news/state-and...cle_934f11bf-8825-5f2f-8391-8cdbe707cd7a.html And in NY they're contemplating sending replacement ballots to 100,000 people who already received one with a misprint.
https://www.npr.org/2020/09/29/9183...to-nearly-100-000-voters-after-printing-error
"We might not know [the winner] for months because these ballots are going to be all over. Take a look at what happened in Manhattan. Take a look at what happened in New Jersey. Take a look at what happened in Virginia and other places." Here the article doesn't dispute that there have been difficulties closing out elections, they just dispute the timing. But a local race that takes weeks to finalize could take much longer on a state-wide scale where they're trying to certify an election. Trump's statement was a prediction and so can't be said to be true or a lie, just his viewpoint.
"They're not losing 2 percent, 1 percent [of ballots], which by the way is too much. An election could be won or lost with that. They're losing 30 and 40 percent. It's a fraud, and it's a shame." They're interpreting "losing" in a way to drive their narrative. It can also mean that you lose that vote in the sense that it can't be counted. As the article notes, many absentee ballots are rejected. And this year the numbers have been higher.
"It's a rigged election." This is an opinion. Lies imply that you have a fact and misstate it. And we don't know yet whether the election will be rigged or not, but there are arguments to be made in support including the changes to the way votes are cast and counted in battleground states.
"Take a look at West Virginia, mailman selling the ballots. They're being sold." This does appear to be just wrong. The only thing I could find was this very minor issue with a mail man who as a "joke" changed party affiliation.
https://www.usatoday.com/story/news...ion-fraud-altered-ballot-requests/5412010002/
"They're being dumped in rivers." See ditch comment above.
"Hey, they found ballots in a wastepaper basket three days ago, and they all had the name military ballots. They were military. They all had the name Trump on them." See Pennsylvania note above.
"[Fraud has] already been established. Take a look at Carolyn Maloney's race." First, voter fraud is real and is prosecuted. As for Maloney's race, I'm not sure about whether there is fraud but they have decided to count ballots that didn't comply with the rules for when they had to be cast.
https://www.nytimes.com/2020/08/03/nyregion/nyc-congress-carolyn-maloney-ballots.html