DZone Refcardz series has 6 reference cards relating to various agile methodologies and practices. These might be useful for high-level overview and quick reference:

  • Agile Adoption: Improving Software Quality (link)
  • Agile Adoption: Reducing Cost (link)
  • Agile Adoption: Decreasing time to market (link)
  • Scrum (link)
  • Getting Started with Lean Software Development (link)
  • Getting Started with Kanban for Software Development (link)

There are also few online agile glossaries which are very comprehensive: