It's Come to This

Congress is looking to returning to fines and imprisonment for witnesses who refuse to testify before oversight committees. (Mostly fines)

This really has not been done in about 75 years, but the increasing assertions of the "Unitary Executive" and the complete capture of the Department of Justice by Donald Trump, leaves only "Inherent Contempt" as alternative:

House Democrats increasingly frustrated by the Trump administration for defying subpoenas are proposing legislation that would ratchet up their power to punish executive branch officials who reject their requests.

Rep. Ted Lieu (D-Calif.), and five other members of the House Judiciary Committee, unveiled a rule change Monday to formalize and expand Congress' power of "inherent contempt" — its authority to unilaterally punish anyone who defies a subpoena for testimony or documents.

Though Congress has long had inherent contempt power, it has been in disuse since before World War II. This power, upheld by courts, has included the ability to levy fines and even jail witnesses who refuse to cooperate with congressional demands.

………

[California Democrat Ted] Lieu's proposal only focuses on monetary penalties. It would establish a process for negotiations between Congress and executive branch officials when disputes arise over testimony and records. The measure would allow federal agencies to lodge objections to congressional requests, and it would permit the president to weigh in and assert any applicable privileges. The measure would also establish a process for holding recalcitrant officials in contempt, including hearings before the full House in which the subject would be permitted to present a defense and would face questions from lawmakers on the House floor.
If the House supports contempt after such a proceeding, it would then vote a second time to impose a financial penalty of up to $25,000. The penalty would be delayed for 20 days to allow for continued negotiations before subsequent penalties may be imposed up to an aggregate of $100,000. The measure would also bar taxpayer dollars from being used to cover any fines assessed through this mechanism.

I would note that while this is rather aggressive by the standards of recent history, but given the level of  disdain shown by recent Presidents in general, and the Trump administration in particular, to Congressional oversight, this is weak tea.