Let's post some game music that originally appeared as instrumental-only (due to technical limitations or otherwise) but actually, it turns out, has lyrics!
The mother (lol) of all examples in my opinion is the Mother vocal album (officially just titled _Mother_) released in 1989, featuring arrangements by Keiichi Suzuki and Hip Tanaka as well as English lyrics penned by Itoi and Linda Hennrick. I don't really know if these tracks were originally meant to have lyrics, but I can't help but love how goofy and earnest they are. I discovered this album well before I had played either Mother or Earthbound while doing a deep internet dive into those (then) mysterious tracks that accompanied the Earthbound stages of SSB Melee. I genuinely, unironically love these songs--so much so that I have about 7 copies on vinyl/CD thanks to the miraculous re-release from Ship to Shore Media in 2015. The whole album is worth a listen in my opinion, but here's "Bein' Friends," complete with Catherine Warwick's odd but lovely semi-operatic vocals:
https://youtu.be/YSshQu9rQLc
The "Eight Melodies" arrangement featuring a children's choir actually makes me pretty emotional (and reminds me of Home Alone 2 for some reason):
https://youtu.be/ZmZMMSDx3Yg
Just last year Suzuki put out another Mother vocal album (Mother Music Revisited) with some new (and sometimes bizarre) arrangements and himself on vocals...it's a bit of an acquired taste (that I may not have totally acquired yet lol):
https://www.youtube.com/watch?v=asi7hMRQ-bE
The entire run of Falcom Vocal Collection albums are essential listening if you want that primo cheesiness factor...I think these were collectively my most listened to albums of 2021. Having only played Ys I, so far, I have not yet appreciated most of these songs in their original context, though I really love what was done with the Feena melody in this track from Vocal Collection IV:
https://www.youtube.com/watch?v=yo3b7HcHSXE
The Chrono Trigger and Chrono Cross Arrangement Album/To Far Away Times from 2015 has a few vocal arrangements. I'm a bit torn on the instrumentation and English lyrics for Corridors of Time, but this version of Schala's Theme is simply gorgeous:
https://youtu.be/F36OnxwYRqE
https://youtu.be/X9snGXp3v3I
And...uh...here's Mario...take your pick I guess!
https://www.youtube.com/watch?v=hYlm_9i5Dgc
https://www.youtube.com/watch?v=65uNCLBTje0
I'm gonna save everyone some time and post this:
https://www.youtube.com/watch?v=B_qnI1WrlnU
And, finally (for now) here are the canonical lyrics for Rainbow Road:
https://www.youtube.com/watch?v=FuX5_OWObA0