Long toss is useful if you're an outfielder who has to make those really long throws to the infield cutoff man or to home plate.
As for running, you're better off doing wind sprints, because they activate those fast-twitch muscles that pitchers need. All that marathon running only serves to tire you out so that you have no energy left to do other necessary things. I used to do lots of wind sprints, and I did a lot of throwing---not pitching, just throwing, as in playing catch. But here's the real key to a pitcher's power---something I call "The Secret".
You've probably noticed that most batters concentrate all their attention on the pitcher's upper extremities, trying to zero in on a nice fat pitch they can blast out of the ballpark, across the street and into Aunt Minnie's kitchen window and smack into the roast turkey on the table. What they don't know is that it's the lower half of the body that's the key, so of course they pay no attention to it. I learned this a long time ago when I watched the Yankees' Big Three pitchers and I saw what they were doing. They were driving off the lower half of the body, using the legs, the hips and the torso in one continuous motion, creating a nonstop flow of energy all the way up through the shoulder and the arm, to the fingertips---and this was how they were generating more power in their pitches, with less effort (even Eddie Lopat who was not a fireballer). They also took a lot of pressure off said arm and shoulder. I realized that this was one way NOT to get a sore arm, and I made a note of it and started working on it on my own. As I practiced this essential element of good mechanics I found that I was doing the same things the pitchers were doing, and although I wasn't a fireballer either I could throw faster and harder, with less effort.
One good way to get the hips, and the whole lower half of the body, involved is something called the "Hershiser" drill which entails no special equipment, just a fence or a wall. And when you combine that with the wind sprints and lots of throwing, you'll find yourself throwing harder---and faster, which is what you want, isn't it? That, in a nutshell, is "The Secret", and it will serve you well. :baseballpitcher: