The neat free web app, created by industrial designer – and former Weta Workshop senior 3D modeller – Jorge Valle lets you create custom checker maps, and download them at up to 8K resolution for free.
UV Checker Map Maker lets you customise pretty much any aspect of a checker map, including the size of the grid and microgrid, the numbering convention (letters and numbers or coordinates), and the colours.
Settings are controlled via radio buttons or on-screen sliders, and there are nice usability options like the one to have the colour of the text change automatically with that of the background for maximum legibility.
Once created, you can download the checker map at resolutions between 1,024 x 1,024px and 8,192 x 8,192px in PNG format.
http://uvchecker.byvalle.com/