Good Visualization of PI Products and which ones you need to build higher tiers.
Quick Info on what Type of Planets you will be able to find in which System.
Diagrams for each Tier 4 PI Commodity in PDF form.
What to extract, what kind of PI to build. Check your estimated profit margins here.
Alternative Visualization of what kind of PI Mats you need for the higher Tier ones.
Collection of Tools for PI and Mining
This site provides market, industrial and general statistical tools
Eve Forum Entry with good PI Setups
All the special Codes for all WH Connections and what they actually mean.
Extensive info on WHs like different Types, their Mass and how to classify them.
General Info about Wormholes like most active corps, activity and their static connections.
Quick price checks for different systems. Accepts multiple copy/paste formats from within eve
Pretty much an out-of-game market where you can check on prices from multiple regions.
third-party market and industry tool. Production-Plans, Bill of Materials, Analysis,...etc
Link to Blog Post with Abyss Info. Blog has multiple other Topics as well.