It's more of a niche thing now maybe but for anyone who still has any interest in picking up games for the 3DS and/or Wii U the time for that is nearly over as they close March 27.
Currently you cannot add money to your 3DS/Wii U eshop account however if your 3DS and Wii U Nintendo Network ID is linked with your Nintendo Account you can add funds via your Switch instead:
nintendolife.com/guides/setup-and-key-facts-for-nintendo-account-and-miitomo-preregistration#how-does-the-nintendo-account-relate-to-my-nintendo-network-id
You can read more about the 3DS/Wii U eshop's closure here:
nintendolife.com/guides/when-does-the-3ds-and-wii-u-eshop-close-nintendo-eshop-closure-guide
If you need an idea for any games to buy, here's a few vids on some that might be worth grabbing:
Edit:
Some more last minute stuff
Some 3DS RPG's:
Some recommended Fire Emblem Awakening DLC:
-The Golden Pack (easy grinding plus an item that gives you a discount at shops)
-Champions of Yore 3 (has a nice skill)
-Lost Bloodlines 2 (new class)
-Smash Brethren 2 (new class)
Some recommended Fire Emblem Fates DLC:
-The version you don't have (Birthright/Conquest) and Revelations
-Map Pack 1 (lots of good things in it)
Some recommended Fire Emblem Echoes DLC:
-The Fledgling Warriors Pack (easy grinding)
-Inner Sanctum (rare items like the nice Star Jacinth)
-Altar of the Savant (helps buff your mages)
-The Cipher Companions Pack (new characters)
-Maybe Lords of the Grave & Flight from the Ruins
Some recommended virtual Console GB/Game Gear titles (tried to aim for things not on the Switch or other consoles):
-Shining Force II: The Sword of Haiya (great bite-size strategy RPG)
-Avenging Spirit (better than the arcade one! you play a ghost that possesses enemies to control them)
-Donkey Kong for the Gameboy (aka Donkey Kong '94 - a surprising classic that builds on the arcade DK with tons of levels)
-Mega Man IV (first Mega Man game with a shop, and a well done game)
-Mega Man V (unique robot masters, also well done)
-Mega Man Xtreme 2 (different level designs and stuff to the first Xtreme which copy pasted stuff, plus you can play as Zero)
-Mole Mania (neat puzzler)
-Mario Golf & Tennis (neat sports RPGs)
-Kokopolo 3D (also a neat puzzler where you slap enemies to anger and lure them)
-Severed (an interesting first person game where you cut through enemies)
For the Wii U:
-Devil's Crush (terrific pinball game)
-Ogre Battle 64 (great real time strategy)
-Noitu Love: Devolution (good platformer)
-Startropics 2 (good lesser known sequel to the original)
-Wario Land 4 (great platformer)
-Final Fight 3 (good beat em up)
Currently you cannot add money to your 3DS/Wii U eshop account however if your 3DS and Wii U Nintendo Network ID is linked with your Nintendo Account you can add funds via your Switch instead:
nintendolife.com/guides/setup-and-key-facts-for-nintendo-account-and-miitomo-preregistration#how-does-the-nintendo-account-relate-to-my-nintendo-network-id
You can read more about the 3DS/Wii U eshop's closure here:
nintendolife.com/guides/when-does-the-3ds-and-wii-u-eshop-close-nintendo-eshop-closure-guide
If you need an idea for any games to buy, here's a few vids on some that might be worth grabbing:
Edit:
Some more last minute stuff
Some 3DS RPG's:
Some recommended Fire Emblem Awakening DLC:
-The Golden Pack (easy grinding plus an item that gives you a discount at shops)
-Champions of Yore 3 (has a nice skill)
-Lost Bloodlines 2 (new class)
-Smash Brethren 2 (new class)
Some recommended Fire Emblem Fates DLC:
-The version you don't have (Birthright/Conquest) and Revelations
-Map Pack 1 (lots of good things in it)
Some recommended Fire Emblem Echoes DLC:
-The Fledgling Warriors Pack (easy grinding)
-Inner Sanctum (rare items like the nice Star Jacinth)
-Altar of the Savant (helps buff your mages)
-The Cipher Companions Pack (new characters)
-Maybe Lords of the Grave & Flight from the Ruins
Some recommended virtual Console GB/Game Gear titles (tried to aim for things not on the Switch or other consoles):
-Shining Force II: The Sword of Haiya (great bite-size strategy RPG)
-Avenging Spirit (better than the arcade one! you play a ghost that possesses enemies to control them)
-Donkey Kong for the Gameboy (aka Donkey Kong '94 - a surprising classic that builds on the arcade DK with tons of levels)
-Mega Man IV (first Mega Man game with a shop, and a well done game)
-Mega Man V (unique robot masters, also well done)
-Mega Man Xtreme 2 (different level designs and stuff to the first Xtreme which copy pasted stuff, plus you can play as Zero)
-Mole Mania (neat puzzler)
-Mario Golf & Tennis (neat sports RPGs)
-Kokopolo 3D (also a neat puzzler where you slap enemies to anger and lure them)
-Severed (an interesting first person game where you cut through enemies)
For the Wii U:
-Devil's Crush (terrific pinball game)
-Ogre Battle 64 (great real time strategy)
-Noitu Love: Devolution (good platformer)
-Startropics 2 (good lesser known sequel to the original)
-Wario Land 4 (great platformer)
-Final Fight 3 (good beat em up)
1 year