As many as you need if you want to discuss specific policies.
1) trump's reduction of Bears Ears by 85%, which not coincidentally, came after significant lobbying from a uranium firm that wanted to mine and develop the area.
2) His executive order to allow employers to stop paying social security payroll tax on low earners.
3) Tax cuts in 2017 which led to the DOW doing nothing for 18 months.
4) The abysmal handling of Covid in numerous ways which led to the U.S. having a significantly higher death rate than the rest of the world.
5) Capping SALT, which has a major impact on me.
6) Stripping the EPA which has and will continue to have major negative impact. The same with the Department of Education.
7) Withdrawing from international treaties which has left the U.S. toothless and helped strengthen our enemies.
8) Screwing up the budget that led to the longest government freeze in history.
9) Loss in reproductive rights.
10) His border dispute with Mexico, his lies, and his policies which wasted money.
11) His SCOTUS nominations
12) Fvcking up the census, which has a major impact on representation and funding.
13) Dreamers
That's just off the top of my head. Allow me to google it, and I am sure I will be reminded of dozens more. Plus, his actions/words had just as much negative impact with non-policy things than those listed above: January 6th, his comments and treatment of allies, his racist/ethnically insensitive comments, his "leadership" exhibited by boasting about his cock size/mocking the appearance of the wives of his competitors, constant attacks on major government agencies leading to public distrust, attacks on the media leading to public distrust, supporting criminals (the chubby. white, young, dork who shot the protester and many others), his urging to use physical violence against protesters, surrounding himself with felons, his promises that have rang hollow, and many more.