The best known blends are with Rock, Soul and Funk which created Jazz-Rock, Jazz-Funk, and the dreaded Fusion. If you can get it Stuart Nicholson's book on the evolution of these styles is excellent. I pointed you towards the Miles Davis end of Jazz Rock last time. Jazz Funk begins and almost ends with Herbie Hancock's "Headhunters" album. So much of the rest of this and the easy listening that often calls itself Fusion is bland and featureless. For me you can pretty much discard anything on the GRP label, but feel free to disagree! The best Jazz-Funk grew out of the Hard Bop and Soul Jazz of the sixties. There are a lot of really good Jazz-Funk compilations about, pick a couple and see if it works for you.
Adding world music elements has been happening since before we knew it was called world music. If I'm honest it's an area that I don't do very well. One artist I do like is Susheela Raman who has mixed Indian music with Western styles more successfully than most others, try her.
Western classical music has been added to Jazz right from the beginning, Ravel and Stravinsky were early supporters. The Modern Jazz Quartet have been as described as Chamber Jazz and that style has evolved into much of ECM record's output. You see what I mean about "house styles" for record labels.
With the current generation of artists the blending of styles and genres has been absorbed as they learnt their instruments so there isn't the rather obvious stapling together of different musics. Electric doesn't mean fusion so much anymore and so on. Portico Quartet use ambient electronic styles. Snarky Puppy bring the attitude of that peculiarly American concept the Jam Band to Jazz with a cast of thousands. Live they are a totally different prospect than their albums. Try this.
My new favourites are a London band The Lydian Collective, they can even sound like the calmer bits of Discipline era King Crimson at times. Try their album on Bandcamp, and look at a couple of their videos. Jazz Mandolin anyone?
This post has become quite long enough already so next time I will talk about the Jazz that is actually on my iPod.