The two biggest IMHO:

Loper Bright could puts every single regulation into question. This would be an earthquake that has to potential to destroy the DC largess that has accumulated for 40 years since Chevron.

Moore v US, screw what you learned in law school, the real test for income goes far beyond Glenshaw Glass as realization of income is not required in order to be assessed an income tax. In fact, the position of the government is that a retroactive tax ON SOMEONE ELSE'S income is just a A-OK. SCOTUS may disagree, and thus greatly narrow what income is, allowing for deferral of US taxation. Actual realization may be required. Or if Moore is upheld, a wealth tax is now authorized. An income tax on ownership of anything is now possible.