Common or Garden Dragons, also spelt as Common-or-Garden Dragons, are a species of Bog Dragon and also the most common dragon (as the name suggests) and can be found in most dragon caves and around the Barbaric Archipelago.
Common or Garden Dragons are meant to be very ordinary and typical of what one would think of when they think of a Western-style dragon. "Common" or "garden-variety" are terms meaning usual or ordinary. According to the "Viking Dragons and Their Eggs" stat sheet, "These are the most familiar breeds - the ones we instantly think of when we say "dragons". As such, Common or Garden Dragons are often green, but can also be yellow in coloring. They have a spade tail, pointy but short back spines, and blunt head knobs.
Basic Brown dragons are closely related and have the same stats and features, though are typically brown and a little larger.
Common or Gardens are said to be the size of a West Highland Terrier (aka Westie).
On the Official How to Train Your Dragon Website, there is a mini-game called "Train Your Dragon" that has a purple Common or Garden Dragon variant, in addition to a more typical green one.
Common or Gardens are not particularly specialized, and are more or less a "garden-variety" dragon. They can speak Dragonese, they can hunt and fish, they can breath fire, and do other basic 'dragon' things, but none exceptionally.
Common or Garden Dragons are perhaps one of the easiest dragons a Viking can train. They are rated a "1" in Disobedience. They are used as hunting dragons, but make good family pets as well.
How to Be a Pirate shows Toothless having eyes that can glow with light in dark conditions (though he later turns out not to be a Common or Garden Dragon). Book 2 further indicates that "One of the only interesting features of the Common or Garden dragon is that its eyes light up in the dark." This light is bright enough for a human to see by, like a flash light.
Hiccup finds a Common or Garden Dragon while looking for a dragon to tame at Wild Dragon Cliff after having given his Basic Brown to Fishlegs. Hiccup claims he could 'sense' the Common or Garden, since it was too dark to see it. Hiccup later names it Toothless. Throughout the first several books, Toothless is thought to be a very small Common or Garden, but later turns out to be a very young Seadragonus Giganticus Maximus. Toothless is also referred to as a Toothless Daydream, a made-up species to make him sound special and fit for a Viking Chief.
Common or Garden Dragons are specifically mentioned briefly as having the ability to emit light from their eyes.
Common or Garden Dragons are shown to be edible, as the Roman Fat Consul eats a dish called "Live Frog and Dormouse Souffles with Common-or-Garden Sauce". Hiccup, Fishlegs, and Camicazi are also served Common or Garden dragons as food while being held prisoner by the Romans.
- "They all refused to eat it when it was fried dragon pie or Common-or-Garden in batter."
- ―Book 3
This offsite mini-game on the Official HTTYD Book Website allows the player to choose a green or purple Common or Garden Dragon to hatch and train.
- While the Common or Garden Dragon from the book doesn't actually appear in the film, the creators developed a dragon to pay homage to the Common or Garden Dragon (especially Toothless) called the Terrible Terror.
- In fact, a subspecies of Terrible Terror exists in the Franchise called the Garden Dragon.
- Common or Garden Dragon in the Hero's Guide to Deadly Dragons on the Official How to Train Your Dragon Books Website.