If you can’t find a chuck roast, keep an eye out for anything that is fairly low in fat, with an even distribution throughout the meat of what fat is there.
Tip: If you’d like to make a lower fat gravy, skip the gravy step and try this instead: Heat low-sodium beef broth to a simmer. Add some of the veggies from the roast and puree with a stick blender. Adjust liquid and veggie proportion until you get the consistency you prefer. If you choose to use a regular blender, keep in mind that blending hot liquids can be dangerous, so a puree first, heat second approach would be safer.