Based on this product's specifications, here are some alternatives and similar models
Vestibule for Octagon Front Extend Tent by COLEMAN, model 2176829, Grey
Summary description:
Vestibule accessory designed for the COLEMAN Octagon Front Extend tent (MPN 2176829). Grey fabric vestibule provides covered entrance and extra sheltered storage space for gear and footwear. Compatible with the specified model to extend living area and protect entry from rain and wind — useful for camping, festivals, and outdoor trips.