Place beans (with sauce), Manwich sauce, and brown sugar in the slow cooker.
Brown ground beef, bell pepper, and onion in a skillet until no longer pink. Drain. Transfer beef mixture to the slow cooker with the pork and beans. Stir to combine.
Cover and cook on HIGH for 30 minutes; then switch to LOW for an additional 1 hour.
Garnish with optional toppings, if desired.
