Rare, yeah, but still a valid possibility. But the main part I wanted to bring up is that the sentence you were referring to actually already includes "scarlet" as an ordinary colour, so the red one in the accompanying picture fits just fine
Or a one note one. But, while I like monstrous races as options, I dislike the trend of 5e to make our characters "special", unique, or noteworthy before the adventuring even begins.
(If this is duplicated for some reason, I'm sorry. It tried editing and that didnt' seem to take, then I tried deleting my original message and reposting. Not sure what's up.)
Counterpoint - PCs are special and unique by necessity. The vast majority of creatures in whatever world your DM runs do not engage in the adventuring lifestyle. Many are happy to live quiet lives settled in relative comfort and peace. When you create a character, one of the things you need to think about is the impetus that sets them apart from those other people that don't delve into musty old tombs and dank caves looking for trouble - otherwise, as soon as the PC gets their hands on a sizable sum of gold, they don't really have a reason not to split and live like a king with the fortune they've amassed. Additionally, characters with class levels are de facto exemplary, and the intro blurb on each class description that everyone skips over to get to the meat of character creation includes questions that probe why your character is interested in sticking their neck out.
That's not to say that you, personally, can't play Johnny Hayseed, the Human Fighter 1 who signed up to be in the army with all his buddies and has no distinguishing features, traits, or characteristics that set him apart from the average person, but as a good player who facilitates the story the rest of the group is trying to tell, you will need a reason to travel with these weirdos who are all strange and different, and that's going to be the thing that sets your character apart.
No argument save that all of that shouldn't make you exemplary or unique in the way the rules present. It makes you motivated. Frankly even class levels shouldn't make you special because everyone should have them. (The NPC classes of 3.5 fell into this trap to for the Warrior and Adept, imo.)*
Johnny Haysee who had some training in the town guard only to lose his family when his village was murdered by a sudden zombie incursion, who then goes on a vengeance fueled life of adventure to gain the power to fight the necromancer that created them isn't any less of a Johnny Hayseed who signed up for basic training, washed out, and then decided to go adventuring. Either can fight but no better than any other guard at lvl 1, because all lvl 1 guards should be fighters (or some other class, not to go too deep down the rabbit hole of "what classes should have what skills in what jobs"). What makes the Adventurer special is their motivation, but their motivation shouldn't start them with super-powers. It should deliver those to them as they explore the world, themselves, and their abilities.
(*) I guess you could define class levels as adventurer only, but even then at lvl 1 I'm not sure you're "better" enough to qualify as meaningful, and in 5e at least its irrelevant because the divorced system between opponents - even npcs - and players means its all nonsensical to justify anyway because the town guard there isn't a Fighter lvl 5 by the rules its a Monster labeled Fighter and will be stated according to what would be a challenge for the DM's needs. Which demands a lot of world based hand waving but that's not what the conversation was on.