My favorites of my old Mocs were Bionicle, but with heavy reliance on System for the details to get a unique feel.
I’ve always thought the Rode looked better on a Toa-sized character…
Some of my first Lego sets were Aquazone, and I always liked the look of that theme.
I had a heck of a time getting all those slope pieces for the prism. Didn’t know about bricklink, had to fill a cup from the wall at the Lego store.
In another timeline, perhaps a Titan from Voodoo Island?
I always try to find odd uses for pieces, like the technic chairs or swivel