Grid Paint is described as 'online drawing tool using various types of grids (squared, triangular, hexagonal). Drawing by grids is something like pixel art, but in pixel art you have only square pixels. Here you have also triangular or hexagonal pixels'. There are five alternatives to Grid Paint for iPad, iPhone, Steam, Mac and Windows. The best alternative is Isometric. It's not free, so if you're looking for a free alternative, you could try TriangleDraw. Other great apps like Grid Paint are IsoSketch (Paid), Hexels (Paid) and Triangle Pixel Pusher (Paid).
Unleash your inner gridded side by effortlessly drawing on an angled isometric grid, creating beautifully precise geometric artwork. IsoSketch is simple and a blast to use. Yet you have full control with color, opacity, fills, strokes, layers, background images, and much more.
Marmoset Hexels™ is a grid-based painting tool for vector art, pixel art, design, and animation. A geometric canvas grid lets artists create complex pixel and vector designs with the stroke of a brush. FEATURES • A totally new way of creating art.