What are the best tools for viewing and editing NFO DIZ files
We have a complete collection of various NFO editors and viewers in our file section under the NFO Tools quick links.
For viewing ANSI or ASCII art I generally prefer ACiD Draw for Windows. While the application has not been revised in nearly a decade it still is 100% operational on modern Windows installations and has some of the best rendering capabilities of any app.
An alternative viewer for Windows would be PabloView for Windows. It too is a long abandoned application that has excellent media support and is fully functional on modern Windows installations.
For conversion of ASCII and ANSI into raster image formats such as PNG nothing beats the open source project that is Ansilove. We used to use this tool extensively here at Defacto2 and can recommend it highly for most people.