Josh Marshall has been arguing that we need a Department of Justice-In-Exile. The idea is that there is obviously a massive amount of law breaking going on, and the Trump DOJ is simply not going to look into it - unless it's a Democrat. In fact, Democrats likely don't even have to break the law to warrant investigation and prosecution. If we are going to fumigate the Executive Branch and DOJ, we will need a repository of evidence so that we may hold people accountable. The signal failure of the Biden Presidency was not throwing Trump in jail on January 21st, 2021.
Now, the obvious problem is that Trump can and will pardon people. Some of the DOJ-In-Exile will perhaps be about sending that evidence to state prosecutors. If Trump pardons, say, Tom Homan, then perhaps Illinois could bring him up on charges under Illinois law.
There's a separate issue that Marshall sometimes refers to, but needs to be repeated. Democrats need to be ready to go on various prosecutions on corruption and fraud outside of the Executive Branch or at least adjacent to it.
Want an example? Elon Musk sure looks like he's committing fraud so that he can become the world's first trillionaire. Given the howling void at the center of this creature in the place where his soul would normally be, his headlong pursuit of "winning" the race to become a trillionaire is naturally the sort of fraud that someone who feels that they are bigger than the law would commit. There's very little chance that Musk will get a pardon from Trump, but he might. He would have to feel that he needed one, and he may be too narcissistic to understand that.
Anti-trust enforcement is a requirement for the next Democratic Administration. Yes, Republicans will caterwaul about "lawfare" after committing actual prosecutorial overreach. You just have to ignore that and bull right through. Biden and especially Merrick Garland were not capable of understanding that. It will require a new mindset from new leaders.