Combine garbanzo beans, dark and light red kidney beans, artichoke hearts, olives, radishes, and carrots in a large glass bowl.
Whisk together the olive oil and vinegar in a small glass bowl. Add the garlic powder, Italian seasoning, onion powder, and black pepper; whisk to combine. Pour dressing over the bean mixture and toss carefully to evenly distribute. Cover and refrigerate for at least 4 hours before serving. Stir every hour to redistribute dressing.