Devices, systems, and methods for treating vascular defects are disclosed herein. One aspect of the present technology, for example, includes an occlusive device comprising a mesh having a low-profile state for intravascular delivery to the aneurysm and a deployed state, the mesh comprising a first end portion, a second end portion, and a length extending between the first and second end portions, and a first lateral edge, a second lateral edge, and a width extending between the first and second lateral edges. The mesh may have a predetermined shape in the deployed state in which (a) the mesh is curved along its width, (b) the mesh is curved along its length, and (c) the mesh has an undulating contour across at least a portion of one or both of its length or its width. The mesh is configured to be positioned within the aneurysm in the deployed state such that the mesh extends over the neck of the aneurysm.