Getting into Commander can be really difficult for newer players who aren’t used to limiting themselves to colors based on color identity, choosing a legendary creature to perhaps build the deck around, and building around the additional 40 cards and the singleton rule. I’ve read lots of places in forums where these players ask for analyses of the number of lands to run. Here I would like to go a step further and provide the a skeleton for the numbers of cards of different types that should be in a deck.
The Commander precons help some with this initial difficulty, but they are not perfect in their design. As anyone who has played those decks unchanged with players piloting their personal builds, the decks are fun but sometimes lacking in some areas. They were designed as stepping stones, and as products for Commander sealed experiences. A skeleton for identifying the minimum needs of a deck would be useful even in individualizing the preconstructed products.
The list will not be comprehensive, and will not be specific in which cards to use in those categories. And of course these numbers are not set in stone, but a basis to begin with. Individual desires on how they want their deck to run and what one faces in a playgroup certainly have effects on the numbers in the list below.
Here is what I suggest:
36 lands (at least 1 basic for each color in the deck),
8 removal spells for creatures and/or planeswalkers,
5 mass removal spells,
5 removal spells for artifacts and enchantments,
5 multiple-use card draw spells,
5 land search spells or mana-producing permanents,
5 spells that destroy nonbasic lands,
5 spells that hate on graveyard effects, which leaves
23 other spells
As I said, there will certainly be arguments against this list. Plenty of players do not recognize the power of pinpoint removal spells, instead feeling Commander players should only run mass removal spells. And the numbers must be tweaked some for the situation; for instance, if you use one-shot card draw spells instead of permanents, you will need more to get the same result. Your deck might be mana-hungry and need way more lands; quite understandable. I merely put what I have found to be the minimum required for 3-color decks. And there is some overlap; some cards are lands and land search, or mass removal that also takes out artifacts and enchantments. Baring a very skewed metagame, the categories above are the bare necessities.
Other categories might be useful: Graveyard recursion and/or cards that shuffle your graveyard into your library, Counterspells, “you have no maximum hand size” effects, tutors, and planeswalkers. I find that these final categories are again important on a case-for-case basis; not every deck needs to reuse its spells or be able to search up its answers, which is why these didn’t make the list but can slide in through the other spells category.
One thing I like about this list is the 23 spaces in the “other spells” category, which allow a player, should they choose, to dedicate a chunk of their deck to their commander, or another theme. If a player did not choose to do so, those 23 spaces could go to increasing the numbers of the other categories, for additional categories mentioned here, or simply for “good stuff” cards that may not fit within the categories of this list. I run three decks that are heavy on theme, but still found room in each for a few “good stuff” cards that I just always wanted to run; those types of cards are great for this format, and if they don’t fit in the other categories, this catch-all is left for them.
If you have any suggestions, make them as needed, provided you remember that this is intended just as a starting point. If you like this idea, disseminate it to newer players you know who have not gotten into the habit of assembling their own decks yet. And in that function, I hope it serves newer players well.