I tried to list all the ways Russia could possibly blackmail Trump...
* The pee-tape, if there is one.
* Trump was actively courted by the Kremlin, KGB in the 1980s and later FSB in the 1990s, with business-opportunities. Russia merely needs to leak old KGB-documents that Trump was meeting with russian agents back in the 1980s and he's toast.
* Trump was laundering money for the russian mob by selling them real-estate on US-soil for cash and without documentation about the buyers. What are the odds that russian law-enforcement did not keep an eye on their mobsters and these mobsters' dealings with Trump? Russia merely needs to leak their police-files how a mobster laundered money through Trump and he's toast.
* Trump was negotiating for a Trump Tower in Moscow until well into the 2016 campaign. He lied about it. Russia can prove that he lied. (Well, Michael Cohen blew up that one.)
* Trump got his money from russian investors. How much do you want to bet that that money wasn't clean? How much do you want to bet that the FSB can blackmail these investors into providing the receipts?
* An internet-server in Trump-Tower was regularly communicating with an internet-server of the russian Alfabank. While the content is unknown, the messages do not fit the profile of simple regular server-handshakes. Russia merely needs to leak that Trump did business with Russia despite the sanctions.
* Jared Kushner and Jeff Sessions had secret conversations with russian ambassador Sergej Kislyak. We don't know what was talked about, but you can bet your sweet bottom that Kislyak has tapes.
And that's not even considering collusion!