Image
• Jeffrey's Image Metadata Viewer to view EXIF or other hidden data in files (unavailable at the moment)
• Enigmatics - Exif as a replacement
• StegOnline for image manipulation (many functions)
• Forensically for image magnification (many other functions)
• Aperi'Solve for steganography
Word
• Qat
• OneLook
Symbol
• ASCII converter, converts from bases 2, 10, 16 and 64
General
• DCode
• Red Luth
• enigmatics.org brute and what it can do
Math