Maybe this is too niche, but would it be possible to have a time filter (probably with a departure / arrival time filter, rather than just a range like morning, afternoon, evening)? My workaround was to copy out the results to Excel and filter it there.
The use case I have was that I was looking for a flight within a month long period, but wanted to find the cheapest flight for a morning departure. (Looking to book a 2 day trip somewhere, didn't care about dates, but wanted maximum time on the ground while minimizing cost). If it's too hard to implement, I'm fine with using Excel.