One of the fun #HomeAssistant related things I did that helps our household out is to find a way to determine when the washer or the dryer have finished their loads. I solved it by getting a smart plug-in switch that does power monitoring, and with some trial and error, figured out how much current the washer and dryer use while in service and how much they use at idle. I used those to create an automation to set a dummy switch to reflect the status of the washer and dryer, and when status changes to "off", it pushes a notification out to the household Discord server so we know when laundry is ready to be moved or pulled. It worked out really really well, and helped remind everybody when it's time to switch without any further intervention.
My next automation project is to do something similar with our portable AC units and couple with IR blasters and temp sensors so that I can make the AC turn on when we reach a needed temp. No manual intervention. I'd prefer central air, but... yanno...