Tommy Emmanuel: Mombasa
Goodbye (original, with non-English captions as a visually grating distraction)
Solo acoustic guitar cover of "Goodbye"
Gabriella Quevedo: solo guitar cover of "Wonderwall"
- - - - -
Grace Gaustad: vocal cover of "Wonderwall"
Two different approaches to devising and playing a solo instrumental version of Nirvana's "Come As You Are" on acoustic guitar.
Jacques Stotzem cover - Come As You Are
https://youtu.be/TLNQiSSrKh0
Alexandr Misko cover - Come As You Are
https://youtu.be/UH2I3pFNeZQ
Here's the "sort of" original vocal version by Kurt Cobain, but backed by a single guitar rather than the band (AFAIK, this isn't that "MTV unplugged" thing back in '93 with an ensemble surrounding him -- OTOH, maybe it is extracted from the same event or another unplugged occasion):
https://youtu.be/GkPBBik4Sjc
There is one part where another guitar does enter, unless Cobain was adept at playing melody at the same time as the two guitarists above. (I very much doubt that.)
For what little it's worth, will embed the first two videos below, even though they'll probably be disconnected within days or less.
Jacques Stotzem
Alexandr Misko
Here is (a somewhat younger) Alexandr Misko playing his solo guitar version of The Police/Sting's "Every Breath You Take". Looks like he's using a 3rd-hand type capo (allows selected strings to go unclamped) instead of an altered tuning, with bass strings muted by a shoestring(?):
https://youtu.be/R0tq85QiHGc
In contrast, this is non-flashy, but virtuoso Soren Madsen just playing it straight minus gimmicks:
https://youtu.be/3DB8O6Yp2RI
Neither of the above videos would embed for even a moment, so that's left to the following, for whatever temporary period...
For a vocal cover of the song, I looked for a minimal singer/guitarist duo who finally had some good audio quality to their recording. That turned out to be a Brazilian couple called Bait 2:
https://youtu.be/BimWM4AwKN4
Bait 2 - vocal cover of "Every Breath You Take"
My absolute favorite performance of that song. The live audience is balanced by a less hammed up singing. So many artists play with their performance the more they do it...usually not for the better. And I like how her voice breaks on the "take me now." Sounds more genuine.