Give your reclaimed boxes and bags a solid upgrade with simple wire handles....

https://victor-wiki.win/index.php/Can_Wire-Handled_Boxes_Work_for_Under-Bed_Storage_with_18-20_cm_Clearance%3F

Give your reclaimed boxes and bags a solid upgrade with simple wire handles. Use 2-3 mm galvanized wire for strength and durability. Drill neat 3-3.5 mm holes to thread the wire through, creating sturdy, easy-grip handles