I totally agree with you about using Google Flights – it's been my go-to for finding good deals. I’ve also had some luck with Kayak, especially when searching for those last-minute flights you mentioned. I tend to travel business class when I can, and I’ve found that sometimes you can score great deals on those if you’re flexible with dates.
It’s always a bonus to fly comfortably without breaking the bank! Another site I came across recently is Travel Business Class (https://travelbusinessclass.com/), which has been really helpful in finding discounted business class fares. So I just wanted to share my experience!