So, you’re creating a character, and want them to be able to adventure into a dimly lit crypt, without the need of sources of light, neither magical nor mundane? Well, you’ve come to the right place, as below, I've chronicled the various ways your Character can have Darkvision.

( Note: Unless specified otherwise, the Darkvision listed have the “you see in shades of grey”  limitation. Also, this is specifically for darkvision, so stuff like truesight won't be listed, even though it’s similar and somewhat better.

Additionally, this is based on the official content I am aware of and have access to on D&DBeyond, and looking for the “darkvision” key word, so please let me know if I've missed anything.)

Option 1: Be born with it, duh. There are many races who have natural Darkvision, such as Dwarves and those of Elvish Blood.

Option 2: Class’ and Subclass’:

The following class’ give the player the option to acquire darkvision:

 Artificers can create the magic item “goggles of night”, and Warlocks can take the “Devil’s Sight” Eldritch Invocation, starting at second level (seen below). (or take one of the pact’s* to acquire “Find familiar” (Seen Below)) (*Pact of the Chain, or Pact of the Tome, with the “Book of Ancient Secrets” Eldritch Invocation.)

Druids can wild shape into Beasts that have darkvision, such as the owl (once the druid reaches 8th level) (lower level options exist, l just don’t want to look through all the beasts to find them)

The following subclass’ get some form of darkvision: 

Twilight Clerics gain the “Eyes of Night” at 1st level, granting 300ft that can see normally, and can be shared with allies) 

Rune Knight Fighters gain the “Stone Rune” which gives 120 feet of darkvision while worn. (3rd level, when they acquire the subclass)

Shadow Monks get the ability to cast the “Darkvision” spell (Seen below) with ki points, when they take the subclass at 3rd level.

GloomStalker Rangers “Umbral Sight”  grants 60ft of darkvision. (or a extra 30 if your race grants darkvision) (3rd level, when they acquire the subclass)

Shadow Sorcerers’ (120 feet at 1st level, and can cast the darkness spell, which they can see inside of if they use 2 sorcery points to cast it.)

Wizards:

Scribes gain the “Manifest Mind”  ability at 6th level, which allows them to summon the “soul” of their spell book, which has darkvision, which it can share with the scribe wizard who manifested it. This works in a similar way to using “Find Familiar” (seen below).

Divination Wizards gain “The Third Eye” at 10th level, which let’s them choose to acquire 60ft of darkvision.

Transmutation Wizards can use their Transmuters Stone (6th level) to acquire Darkvision.

Also, Arcane Trickster Rogues and Eldritch Knight Fighters eventually gain access to the “Darkvision” spell (seen below), because they use the wizard spell list, which is why they’re here, below the Wizard.

Option 3: Magic. You could learn and cast the 2nd level spell “Darkvision”, granting 60ft of darkvision for 8 hours, use the uncommon magic item “Goggles of Night”, or, theoretically, use the wish spell. Taking the “Eldritch Adept” Feat for “Devil's Sight” (normal sight 120ft ) also counts, In my opinion. You can also cast the “Find Familiar” spell, to summon a creature with Darkvision, such as an owl, and see through their eyes.

 In conclusion, if you want the best possible darkvision as soon as possible, choose a Vuman or custom lineage, give them the Eldritch Adept feat for devils sight, (mostly for the vision in magical darkness) and make them a Twilight Cleric.

 (Ps, it's kinda funny how the wizard get like, 5 different options for getting darkvision, two of which are available to all wizards. It makes sense though. D&D wasn't made my Druids of the Coast afterall.)

And there you have it. All the ways I know of to have Darkvision in D&D 5e, as of November 7th, 2021. Please let me know if I've missed any. 

Can I suggest mentioning the levels for Option 2? You have done for Wizards and Shadow Sorcerors, but not the others, and it could be relevant. For example, Gloomstalkers only get it at L3, which is a bummer - you want to use them for primarily dark environments, but you might also want to use a race that doesn't naturally have it to avoid doubling up on abilities, which makes L1 and L2 rather painful.

Right, fixed, thanks.

Nice guide. Thanks!

Since this guide has been made, another option has appeared.  From Bigby Presents: Glory of the Giants, the Keenness of the Stone Giant feat grants 60 foot darkvision to whomever takes it (or increases existing darkvision by 60 feet).

Just in case anyone wonders, Darkvision doesn't allow you to see in magical darkness.