Welcome to the club! That's a heck of a list already. Another big hit for me is ensuring your thermostat is set seasonally (warmer in summer, cooler in winter), your weatherstripping seals doors & windows, & you have appropriate sunshades or curtains to control indoor temperatures as passively as possible - some money will always be going out for utilities, but passive reductions in use add up fastest. Real insulation in the structure is vital but can only do so much if the house is drafty. Organizing your errands for minimum driving pays off surprisingly quickly, too. If you want to take on additional projects, making your own pizzas is somehow still cheaper than frozen, plus often tastes better. Check out the sub-$200 grocery budget thread for inspiration. Paper egg cartons are the best for starting seeds, if you eat eggs.
I suppose if you want a "frame of mind" question, I was surprised to read you threw out your reusable toilet cloths given everything else you said about them. I can understand "normalizing" some habits for household harmony with roommates, especially if it's temporary, but why would you throw them out altogether? (But then that's MY inner 80-year-old talking.)