Which type of stocks creates difficulties during tax filing season?

I have been looking at a few stocks traded by the politicians, esp. pipeline stocks like $ET, $ETRN, $ENLC etc.

When I tried placing an order, Fidelity gave me a pop-up of it being an MLP. I quickly looked up and realized that it could be a tax headache, even if held in HSA.

Others are K-1 (if I understood correctly).

These stocks are attractive with a hefty dividend yield, but are they worth the headache?

I wonder if there is any comprehensive write-up for an average Joe to understand.

Thanks in advance.