In terms of layout, I use a variant of Colemak called Colemak DHm. I have also opted to mirror my mod keys, including Shift. Additionally, I have swapped my Lower and Raise keys to match my intuition of “lower” to be base symbol and numeric keys and “raise” to be the shifted versions. Finally, I have mapped ARST (Colemak home row) to be my arrow keys in a Vim-like style when I am on the Raise layer.
For my keycaps, I kept the black keycaps that came with the Planck EZ for the most part and only replaced the T and N keys (right-most and left-most home row keys) with blank blue keys that have a slight indentation. This was done to sense by touch whether my fingers are at home position on the keyboard.
My dream setup would have coiled aviator cables that color-coordinate with custom keycaps. I haven’t quite figured out my desired color scheme but blue would be prominent in it. I would also like the keycap symbols to be Japanese.