3. 1B Pete Alonso
This one seems more realistic than the others somehow. Similar to the Padres, the New York Mets have a massively inflated payroll but a lackluster record of 42-48. Things could change between now and the trade deadline, but if the Mets do decide to sell (very unlikely I know), Pete Alonso would be an intriguing chip. He has one more year of control before hitting free agency in 2025 so he probably won't command the type of capital a Rafael Devers trade would and he would be a great fit with the Cubs.
Yes, we would still probably have to move a top prospect like PCA, but it might be worth it to get Alonso. He's made 3 All-Star teams, he's always near the top of the league in home runs and RBIs, he's under 30 years old and the Cubs need a 1st baseman. Alonso would be a great fit and the Cubs might want to explore this option to get some more power in their lineup.