Tiled2Bin
This is a tool to convert maps built in Tiled to binary files that can be used on the next.
Tiled2Bin Download Page
PalEdit
PalEdit is a palette editor which can edit and manipulate various different palette and graphic formats.
PalEdit Download Page
Gfx2Next
ZX Spectrum Next graphics conversion tool.
Gfx2Next Download Page
Bitwise Calculator
Bitwise Calculator is a Windows binary, hex and decimal converter with logical bitwise operations.
BitCalc Download Page