Three things he said he would do come to mind immediately:
"When I win, I will immediately bring prices down, starting on day one."
"They're dying, Russians and Ukrainians. I want them to stop dying. And I'll have that done - I'll have that done in 24 hours."
"On January 20th, as one of my many first Executive Orders, I will sign all necessary documents to charge Mexico and Canada a 25% Tariff on ALL products coming into the United States"
None of those things happened.