The biggest savings for me were travel (mostly commuting) and food.

During the ~15mo I worked fully remote during COVID, I put just a little over 1000mi on my car. The bulk of that came from a single day trip to an IKEA ~150mi away to buy furniture.

I also made a pot of coffee in the morning and ate a sandwich or leftovers on my deck for lunch as opposed to spending ~$20/day on coffee and lunch from restaurants near the office. That's an extra $100/wk in my pocket from food alone.