While the core of MTG is its gameplay, I would argue that what keeps players captivated in this 28+ year old card game is its immersion and storytelling. Perhaps the most iconic form of lorebuilding in the game is its loyalty to the "color pie". The color pie is the idea that each of the five colors in MTG adhere to a certain set of gameplay and storytelling principals. Not only does this change how cards are presented in the form of their art, card name, and flavor text, but it manifests itself in the actual gameplay, as certain mechanics tend to be unique to certain colors or color combinations. While certain gameplay mechanics are not stricly limited to one color in the rulebook, certain gameplay mechanics, ones that fit the theme of a color, tend to be present most often in that color. Another important worldbuilding mechanic in MTG is the "flavor text". Flavor text is a short snippet of italicized text placed at the bottom of some cards. While it has no bearing on gameplay whatsoever, it is used to give players a sense of how the card fits in to the greater fantasy universe that Wizards of the Coast has created for MTG.
Allow me to provide an example. The card Sign In Blood reads: "Target player draws two cards and loses two life". Even without seeing its art, we can tell this card deals with sacrifice; the player must first suffer (lose two life) before being rewarded with a greater benefit (drawing two cards). The card's flavor text echoes this sentiment: Little agonies pave the way to greater power.
On top of the five basic colors of Magic, multicolored cards can be guessed by selecting the gold mana type (with the circle in it), and colorless cards can be guessed by selecting the silver mana type (with the diamond in it).