I was asked recently online if it was possible to break up the repetition of a tiling texture with Unreal and, of course, it is!
If we just create some variations of our input tiles (here I’ve just offset and rotated them in the material) then we can just use a grid mask texture, with 3 sets of random grid layouts channel packed into R, G and B, and Lerp between our variations - and if we change the tiling scale of our masks we can create near infinite variety!