I mean you can create gradient materials or base colors (or basic textures) it’s super easy. The program you need for those materials is called blender
First, open the blender meet with default cube.
Second, open viewport shading and set color to vertex
Third, give more geometry to your shape with subdivision surface modifier or etc After that apply the modifier
Fourth, change object mode to vertex paint
Five, Start painting be creative to earn new results
Also make sure use mirror if you want do same strokes to other sidesI ended up with this weird shape
Now you can export as .fbx or .obj

after that add a mesh part import your mesh
now your mesh have 3 type of textures
1 vertex paint
1 roblox material
1 brick color
feel free to adjust them
your mesh can have shine effect too or forcefield I mean be creative and enjoy with your gardient or colored mesh or brick
(sorry for grammer issues)