Geocaching

• Cachetur - Geocache route planner
• Upcoming souvenirs
• Map with proximity overlay

Puzzle solving tools

• Geocaching toolbox
• CacheSleuth: Collection of codes, ciphers and decryption tools. [Created by u/cachesleuth]
• dcode.fr: Cipher tools.
• quipqiup: Automatic monoalphabetic substitution cipher (cryptogram) solver.
• CoordCalc: Projections, circle intersections, etc.
• WikiBruce: More links to even more tools! [Created by u/thebruce0]
• Boxentriq: Dozens of cipher types as well as a Cipher Identifier