The list of most likely is spending. Another stimulus bill, healthcare bill, environmental bills... trillions in spending in the near-term is nearly guranteed.
Less likely is to tax the rich. First of all, the tax revenue from the rich is somehwat elastic- if the cost of paying taxes goes up that gives them an incentive to spend money on sheltering their income from taxes. Second, when we say rich we actually mean wealthy, and there is no good way to tax accumulated wealth. That means that any tax increase plan has to also include the top half of the middle class (executive white collar) in order to raise significant revenue.
Giving back what's been taken away hardly ever happens. Dont count on getting back SALT deduction. That benefits the middle class and neither party is known for doing that.
It will be up to some of the Dem Representatives to come up with a M4A plan and try to push it through but I have my doubts that the medical insurance industry will be overcome even with full Dem control