In some embodiments, containers, bags, and systems are provided that are useful to organize tools and other items. A tool bag may include a container body including one or more woven panels, a bottom rigid member, and a rigid wall hingedly connected to the bottom rigid member, and an engagement mechanism attached to the rigid wall. The engagement mechanism may include a base panel riveted on the rigid wall, and one or more protrusions extending from the base panel. In some aspects, the one or more protrusions are configured to engage with one or more holder slots on a ladder top.

A portable, collapsible modular container system for transportation and storage is provided. The containers are modular and can be staked in either extended or expanded position, collapsed, or a mix thereof. The container system is modular and customizable, and attachments such as wheel, handles, carry straps, tie down straps, and other accessories, may be added or removed at the option of the user.

Collapsible travel cases are provided herein. In some aspects, the collapsible travel case is configured to store a bicycle when the collapsible case is in an expanded configuration. In some aspects, the collapsible travel case comprises a base that is configured to fold at a joint via a hinge assembly.