Since the Democratic attack on President Trump for colluding Russia to win the 2016 election seems headed for failure, they will switch their attacks to looking for financial crimes. I think it will be easy to find some questionable things that Trump has done in the past, but it will be less clear whether they rise to the level of serious crimes. What they find is unlikely to be campaign related, except for the payments to the two women, Stormy Daniels and Karen McDougal. Other misdeeds probably predate the campaign and prosecuting them will smack of political motivations, rather than legal ones. If he did something wrong in 2012 (or whenever) he should have been accused and prosecuted then, not now.
The Democrats moved too quickly on the collusion with the Russians allegation. They were the ones who decided to believe the internet rumors and innuendo, the Facebook myths about Trump. They were actually accusing Trump of treason. Trump may be a lot of things, but he is probably not a traitor. He believes to the bottom of his heart that he is not a traitor, and that is why he found the allegations so abhorrent. I find it interesting that his harshest accusers were mostly Jews, who often have divided loyalties, whether they are more loyal to Israel or the United States. Adam Schiff and Jerry Nadler appear to be hypocritical, two-faced accusers. They enter this battle as soiled as Donald Trump.
On the other hand, impeachment is not about law or justice; it is about politics. If the Democrats can persuade enough of their colleagues to vote for impeachment, Trump will be gone. But with a Republican Senate that will be hard to do, unless some new really sordid scandals (worse than all the sordid stuff that has already come up) come to light.
The Democrats have a better chance of indicting and convicting Trump after he is no longer President. If they do, it will look a lot like sour grapes and political retribution, but it may stick.