Are there any existing magical/artificial replacement arms written up?

Question

So I lost my arm after shoving it into a cube and it getting cutoff... Honestly, I have been playing my character Wyn Wynn as a pretty straight forward Paladin of Lathander. I am new to the group I play with and the DM and players have given me credit and said I have been playing my character well and even like him as a character even if sometimes my character butts heads with one of the other characters. But now I want to stick out a bit and claim some glory for my own.

As I said I have just lost my arm, fun stuff truly but as luck would have it, we accepted a quest that if we clear out the tomb, we all get one wish. Now, assuming great Wyn Wynn the now one armed badass paladin lives, I was wondering: are there anything written about having an artificial limb or magical one in any of the official 5e D&D handbooks? I am hoping to wish myself a new arm that is magical or artificial. Not that my old Half-Elf arm wasn't great, regrowing it just isn't what I am looking for.

Answer 1

The book Eberron: Rising from the Last War includes the prosthetic limb magic item (page 278):

This artificial limb replaces a hand, arm, foot, leg, or similar appendage that was lost or removed. While the prosthetic is attached and attuned to you, it functions identically to the body part it is replacing. You can detach or reattach it as an action, and it can’t be removed by anyone else.

If you have multiple prosthetic limbs, they count as a single magic item with regard to the number of magic items you can attune to.

Ventilating lungs (found on page 279), a prosthetic set of lungs, are also listed:

These metallic nodules were created in response to the poisonous gases used on the battlefields of the Last War. When you attune to these lungs, they replace the lungs in your chest, which disappear. The lungs allow you to breathe normally, even in an antimagic field, and their breathing function can’t be suppressed by magic.

Answer 2

Yes. Man, are you in luck.

The DMG details two such replacement limbs as magical artifacts- The Hand and The Eye of Vecna. Both of these items replace original body parts, and grant a number of randomly determined enhancements (20 STR score or permanent True Sight, for example), as well as an Evil alignment. The Hand specifically call for the intended user to lop off their own left hand, which might fit your specific circumstances (and depend on just how much arm was lost).

Obviously, as artifacts of an undead god of secrets and magic, these are tremendously powerful, and you should consult your DM before attempting to quest for them.

Answer 3

The 'Regenerate' spell.

It's a 7th level transmutation spell (PHB. 271) which has besides the healing the following effect:

The target’s severed body members (fingers, legs, tails, and so on), if any, are restored after 2 minutes. If you have the severed part and hold it to the stump, the spell instantaneously causes the limb to knit to the stump.

Answer 4

I don't believe this option is as suitable as the existing one by user60611, particularly with regards to something being granted by a wish, but for the sake of completeness:

Three levels of Artificer

At third level, an Artificer can gain the Armorer specialization as detailed in Tasha's Cauldron of Everything, which in turn grants the Arcane Armor class feature. This feature would allow you to:

As an action, you can turn a suit of armor you are wearing into Arcane Armor, provided you have smith’s tools in hand.

And the Arcane Armor created by this feature has several benefits, most of which are irrelevant, but this is included:

The armor replaces any missing limbs, functioning identically to a limb it replaces.

As-written, it's not possible for an Armorer to make an Arcane Armor for another creature, or loan their own armor, so RAW you would need to actually gain 3 levels of Artificer in order to get this feature, which could be beyond the purview of a wish but is an option if you're willing to spend time gaining levels instead.

Your DM might be willing to homebrew a magic item that replicates some or all of the features of Arcane Armor without requiring Artificer levels, but that's definitely not in any "official 5e D&D Handbooks".