3-Manifolds: Links to low-dimensional topology resources.
Crystallographic Topology: The Topology of Crystallographic Groups and Simple Crystal Structures
Geometric Topology: Numerous links in the Geometry Junkyard.
Manifolds and Cell Complexes: Section 57 in Dave Rusin's Mathematical Atlas.
The Optiverse and Other Sphere Eversions: Article by John M. Sullivan on sphere eversions, with numerous illustrations.
xxx Math Front: GT Geometric Topology: Preprints in geometric topology in the Arxiv.