trail maps:

• corridor map
• South Rim Information and Maps longer pamphlet
• incredible geology map

trails / routes / projects:

• hiking
  • WIKIPEDIA
  • everytrail.com [2]
  • backpacker.com
  • nps.gov
    • day hiking trails
    • trail distances
• bouldering
  • "endless options", basically
  • Google Images search
  • @mountainproject.com

specific trails

• Bright Angel Trail [bobspixels] [everytrail] [backpacker.com] [NaturePod]