In Mode1, the limited set of inks (only 4 ink) need a proper colour management.
The following was often certainly the best one, it is probably the technique used in head '''Head Over heels Heels''' :
***Background : can be in 4 colours, it is used for the floor, HUD and backgrounds walls only. You can use a set of 2D tiles with no mask and those can never be "foreground"
***Sprites and fore-ground elements (objects, doors, platforms...) : they use only 3 colours and the 4th ink is used to get the mask.
'''Heroquest ''' per example is quite similar.
The floortiles floor-tiles and background walls are masked, the "4th colour " (grey, actually ink0) is nearly never used except for the "emptyfloor" or the "Mouse cursor"... A clever use of the transparency with /mask ink on the Floor/Wall tiles could enable to display this backgriound grey on those floor/wall tiles but it wasn't done... which is a serious graphical limitation alongside a poor colours choice. It is also to notice that the basic floor tiles use only 2 inks (Blue and dark blue) the "light cyan" seen in the jointed floor-tiles being sometimes obtained with the pixels-crossing of pixels from 2 tiles different.
==Pixel Art==
Isometric is often used in classic Pixel Art and is emblematic of it as it was the best way to display good looking pseudo 3D FX on old computer 2D systems.