In which I spend an hour (!) rambling on about Old-School Essentials, basically the Gold Standard in the OSR D&D sphere as far as I'm concerned. I love this book (these books?) and you owe it to yourselves to go through them and see what you use in your own games. Even if you end up discarding many ideas, there might be something that will work out really, really well!
Here's where you can find out more:
https://necroticgnome.com/pages/about-old-school-essentials
Music from lots of great video games that you should play!