An electronic device comprising lower and upper decks adjacent to a source. The lower and upper decks comprise tiers of alternating conductive materials and dielectric materials. Memory pillars in the lower and upper decks are configured to be operably coupled to the source. The memory pillars comprise contact plugs in the upper deck, cell films in the lower and upper decks, and fill materials in the lower and upper decks. The cell films in the upper deck are adjacent to the contact plugs and the fill materials in the upper deck are adjacent to the contact plugs. Dummy pillars are in a central region of the lower deck and the upper deck. The dummy pillars comprise an oxide material in the upper deck, the oxide material contacting the contact plugs and the fill materials. Additional electronic devices and related systems and methods are also disclosed.