• Anatomical Labeling
  • Anatomy Toolbox
  • SUIT - Cerebellar Spatial Normalization
  • WFU_PickAtlas
• Image Processing
  • Volumes Toolbox
  • Masking Toolbox
• Times Series Processing
  • MarsBar
  • REX Toolbox - Region of Interest Processing
  • ART - Artifact Detection and Repair Toolbox
  • ArtRepair - Artifact Repair Toolbox
• Connectivity
  • Connectivity Toolbox - Functional Connectivity Analysis
  • REST - Resting State Analysis
• Multimodality
  • Diffusion II - DTI Analysis
  • FieldTrip - MEG and EEG Analysis
  • NIRS SPM - Near-Infrared Imaging Analyis
• Morphometry
  • VBM Toolbox - Voxel-based morphometry

Not all of the listed extensions are yet fully compatible with SPM8.
 
To explore more extensions, go to the SPM Extensions site