Combine eggs, diced onions, bell peppers, ketchup, milk, onion powder, salt, and pepper in a large mixing bowl.

Crush the saltine crackers into fine crumbs and fold them into the mixture.

Gently fold in the ground beef until just combined.

Shape the mixture into a loaf and place it in the slow cooker.

Cover and cook on LOW for 5 to 6 hours.

Mix ketchup, brown sugar, mustard, and Worcestershire sauce to prepare the sauce in the last 30 minutes of cooking.

Spoon the sauce over the meatloaf and cook for an additional 30 minutes.

Let the meatloaf rest for about 10 minutes before slicing.