Almost every kind of wood I wish I didn't have. In SW Idaho, we have literally nothing but softwoods. I have Doug Fir 2x12 boards, some white and grand fir, plenty of ponderosa and lodgepole, and a bit of tamarack (western), all sourced from nearby Payette National forest. If you're a scrounger like me around here, you'll only be disappointed. Down here it's desert like northern Nevada, so most scrounge finds here are sh*t maple (silver, smells like a buck of bluegill), poplar (don't get me started), willow (I only use it for black powder charcoal), and cottonwood (the holy grail of awful smelling foulness). However, if you're willing to knock on a couple of doors, a lot of river bottom properties will have a grove of Black Locust they're happy to be rid of, and usually can be had free if you're willing to clean up thorns and kill the underground runner so they don't come back. No other hardwoods are available,with one exception. I'll segue into that in a minute.
If you're willing to drive around all day, there is also a lot of Juniper in the Owyhees that the BLM lets go on permit for 1 dollar per cord, and it's decent stuff if you can stand the smell (which I happen to like). The real treasure is when you find a dead and downed Mountain Mahogany near the Juniper. You can't cut them even standing dead, but I'll snag one on the ground every so often. It is the best firewood I have ever used, it's relative density is 1.11 (meaning it will sink like a stone when dropped in water), roughly 1.5 times that of oak or locust. It's right up there with Hop Hornbeam/Desert Ironwood, smells much better, and it's a dang sight better than Osage Orange in BTU output. A few years back a guy on arboristsite.com in my neck o' the woods got some and did an endurance test in his Blaze King, and still had coals and heat output nearly 48 hours later, all in single digit temperatures outside. Most of what we have is doodoo, but a couple are excellent.
In the future I'm going to switch to mostly juniper. The high altitude ones we have in the Owyhee mountains are really dense for a softwood, 10 percent or so more than our next best conifer, Tamarack. My buddy had some still green, and when I picked a round of it up, the best guess i had (based on weight) was Shagbark Hickory. I was wrong. So I bummed a couple rounds to split and try, and after seasoning I got a better burn time from it than when I was burning cherry or apple (which are likewise hard to get even with all the orchards around here). The mahogany is great stuff. Perfect BBQ wood, and it lasts longer and is easier to control than even anthracite in a hand fired stove. One day if I ever find a piece straight enough, I will have myself one heck of a beautiful rifle stock.