I'm creating an extremely difficult regex challenge that combines multiple complex pattern types with tricky edge cases. The challenge includes:
1. Valid IPv6 addresses in different formats (compressed and uncompressed)
2. Valid UUIDs with specific version requirements
3. Credit card numbers with various formats and valid checksums
4. Items that look similar to the targets but should be excluded
5. Patterns requiring lookaheads/lookbehinds to match correctly

This will require handling different... (truncated)