So you don't expect they are uncovering tax fraud, money laundering, accepting bribes, and violating the Emoluments Clause? As for not touching Trump, if his kids are charged you know he'll pardon them and the GOP won't care...
I really don't know what the evidence against Trump is right now or for what crimes. I think Trump has routinely broken laws throughout his life in all kinds of ways. There are many issues as to whether this kind of stuff will lead to his being forced out of office.
1. As I mentioned above, crimes that were for the purpose of getting him elected will be largely excused by his supporters. Impeachment/forcing a president out of office is political and absolute proof of this kind of crimes might not be enough to lead to the forced removal of Trump from office.
2. Unequivocal proof of quid pro quo arrangements with the Russians would probably lead to the forced removal of Trump from office, but this kind of crime is difficult to prove in unequivocal ways and any wiggle room will be enough for Trump's supporters on this.
3. There may be evidence of Trump's cooperation with organized crime. This might be accepted by partisans as Trump just acting in the way that was necessary for the kind of business he was in. Not enough is known about this right now to make a very good guess IMO.
4. There probably is more evidence to come out of Trump's racist chit chat and Trump's misogynistic ways. A lot of Trump's supporters are mildly to strongly racist so this won't bother them all that much. More Trump racism will make it difficult for Fox News because advertisers who are trying to sell stuff to everybody won't subsidize Fox News support of a racist president.
5. Trump's relentless corruption with regard to the way he exploits the presidency to line his pockets is unlikely to do him in IMO. The Republicans have essentially acted to allow it. It is hardly any kind of crime if it is accepted by congress. He might lose some court decisions on this but they won't do him in IMO.
6. Trump seems to have violated some laws with regard to his willingness to do business with Ukrainian and Russian organized crime. I don't think enough is known publicly about this to make reasoned guesses as to how this might go. Cohen and potentially Manafort probably know what the extent of Trump's crimes are with regard to this. It may not be essential that either of them flips on Trump to do Trump in. There may be enough evidence on this with what was seized from Manafort and Cohen to do Trump in or possibly not.
7. Various income tax violations are another area where Trump might be at risk because most people don't honestly report their income from illegal activities. Again not enough information about this is public right now, but doing Trump in for income tax violations doesn't seem likely to me.
ETA: I should have added his foundation BS to the list
8. Trump and his children are in trouble because of his foundation shenanigans. It will be embarrassing for Trump and dangling pardons can't help him because a state is prosecuting this. I don't expect this to do him in either though. He will try to pay some fines and end it. He will falsely claim it is a political prosecution (he's already doing that) and that will be enough for his supporters. While he is in office the state can't prosecute him anyway, but the prosecutions of his children will be interesting.