the blue keys are visual aids for hand placement, including thumbs. these aren't entirely original ideas, and may be completely identical to some others, but not to my knowledge. i only used standard sizes of keys, but not standard for how some of them are labeled. the two bottom layouts assume you would be using space/enter as modifier keys, such as a planck would.
the first layout reduces the amount of stagger on the numerical and bottom alpha row.
second is a mirrored staggered layout. this one also has the stagger reduced like above. the extra key next to shift is there because keycaps don't normally come in the width to fill that space.
the third is kinda like a lot of other split-hand staggered layouts, but with a slightly different stagger and kept fairly minimal.