TLDR: The new Virtual Game Cards update lets you lend discontined games. I tested it with Minecraft Nintendo Switch Edition (the old version of Minecraft that was delisted in 2018), and I was successfully able to lend it to my friend for two weeks.

I've just discovered that unobtainable digital-only games can now be lent to people using the new Virtual Game Cards that were just introduced in the new update for the Nintendo Switch.

I have Minecraft Nintendo Switch Edition on my Switch. I bought it in late 2017, and it was delisted from the eShop and replaced with the bedrock edition of the game in 2018. The bedrock edition of the game, simply titled "Minecraft" is the only version you can buy anymore on the Switch, and is available both digitally and physically.

Sadly, the original Nintendo Switch Edition never got a physical release, as Mojang's plans to do so were cancelled once they decided to replace the game with a new version. As a result, it's almost impossible to legally obtain a copy of the game anymore.

I just went to my friends house today, to test out the game lending. We decided to try out Minecraft Nintendo Switch Edition (the discontinued one). And I can confirm that it worked! Once I sent the "Virtual Game Card" over to him, the game popped up on his Home Menu and began downloading.

I also have another game that will probably work with game lending, but I haven't tested it out yet: Fire Emblem: Shadow Dragon and the Blade of Light. The game was a Switch port of the original japan-exclusive NES game, and released in 2020 as part of Fire Emblems anniversary. Similar to Super Mario 3D All-Stars, it was a limited time release. But unlike Mario, the game was digital only. It's also the only official English translation of the game, so it was kind of even more stupid that they delisted it permanently. Either way, I haven't tested that game out yet with game lending, but I don't see why it wouldn't work if the old Minecraft did.