In a previous post I defined several card roles in Magic the Gathering (MTG). For me, a card role is a way to categorise a card independently of its colour, type, name, and other official identifiers. I believe this makes casual deck building relatively easy, and that's my primary interest. I'm not a competitive or even extremely strategic MTG player. I play the game because I like the cool pictures on the cards, and I enjoy the unexpected rules exceptions that so many cards represent. For me a deck is one that provides me with enough mana to summon creatures and cast spells, and enough creatures and spells to stimulate my imagination.
I didn't invent card roles. "Real" players of MTG often talk about a card according to its role, and it's from conversations and podcasts and articles about MTG that I've derived my list:
The most efficient way to acquire cards within each category is to search the Internet for cards that fall within those categories, and then buy the ones that appeal to you as single cards from your game store.
It's easy to over-think the process of building a deck, to the point that many people who get overwhelmed and just never build one. Here's my schema for building a 60-card deck:
Replace Strategy of your choice with exactly 1 card role. Don't try to cram too many roles into a single deck. Focus on a single strategy.
For the Mana ramp and Card draw cards, favour low-cost cards, using mostly 1-drops, 2-drops, and maybe 3-drops at the upper end.
For the Strategy of your choice cards, favour expensive cards, using mostly 3-drops and above. These are the cards that exemplify your chose deck strategy. They'll cost you, but because you've got cheap mana generation and card draw, you should be able to afford it when you need it the most.
First of all, this deck building hack doesn't work competitively. Its only job is to make fun decks that enable you to actually play the game. This is NOT the way to design decks that "slay the meta" and win championships. This hack enables you to build cheap (dollars not mana) decks from lots of table chafe and a few expensive (dollars not mana) purchases for specialty cards (like Sol Ring and Basic Lands.)
The reason the hack works as a quick and cheap way to build a deck is because it abstracts the roles you need to fill in a deck away from a specific card. If you look at winning decks, you notice that most contain many copies of identical cards. A pro player doesn't just take Squirrel Sovereign, a pro player takes 4 Squirrel Sovereign. Taking as many identical cards as possible is a way to minimise randomness in a deck, but it's also expensive (in dollars) because you have to find 4 copies of the same card. What's less expensive (in dollars) is identifying what role a card plays, and then buying any number of cheap (in dollars) cards that fill the same or a similar role.
Having said all of this, I must admit I've moved on from Magic the Gathering. There have been several reasons for losing interest in MTG over the past few years, but the most fun reason has been Flesh and Blood. The game is only similar to MTG in the sense that it's a trading card battle game, but it nevertheless satisfies the same compulsions. You can build decks, manage resources, and battle other players. What it lacks in rules complexity, it makes up for in nuance and strategy. It of course probably wouldn't even exist if it hadn't for MTG paving the way for trading card games, but by benefit of learning from games that have come before it, Flesh and Blood is unquestionably superiour in game design. I doubt I'll even buy another Magic the Gathering card unless it's a historical one I'm buying for its art, and maybe some day I'll be good enough at Flesh and Blood to jot down my strategic notes. Probably not any time soon, but it's fun trying to get to that point!