the official canon states that tieflings can’t be purple, and yet the official artwork for a tiefling is a purple tiefling
Official Dragonborn PHB description say Dragonborns are brown/rust coloured, with some being rust-copper green.
Artwork on the same page is a red scaled dragonborn.
The full sentence is “Their small, fine scales are usually brass or bronze in color, sometimes ranging to scarlet, rust, gold, or copper-green.” So a red one is kinda like a real life human with ginger hair; uncommon, but not weird. There’s also the bit about dragonborn with a particularly strong influence of their draconic ancestor shortly afterwards that says, “These dragonborn often boast scales that more closely match those of their dragon ancestor - bright red, green, blue, or white, lustrous black, or gleaming metallic gold, silver, brass, copper, or bronze.”
You omitted that the draconic colored scales are from extremely rare and isolated clans.
Possibly the most ignored sentence in the PHB, even by Wotc themselves:
Their skin tones cover the full range of human coloration, but also include various shades of red.
I can do you a few of the most ignored pages in the PHB: I’ve yet to meet a table that uses Trinkets
I had a Tortle Kensei Monk (Ninja Turtle) that had 77 on the trinket table. “A gemstone that looks like a lump of coal when examined by anyone but you.” In one of dungeons we were in, I lost it trying to bribe our way out after the BBEG captured us. I was bummed about it ever since, it was my prized possession. Later on in the campaign I came across a genie who asked us to run off or kill the Aboleth that had taken over his home. In return he would grant us a wish. I’ve never come across a genie ever in my 25 years of playing DND. The group was reluctant to fight it, so I lied and told them we would all get wishes. We defeated the Aboleth and go to ask for wishes. I ask him if we can all have wishes and he shuts that down fast. Before the group can come to a consensus about what to wish for, I blurted out that I wish for my trinket back. Poof, it appeared and now I’m one happy tortle. My companions, not so much.
