BONUS MARIO PAINT TIER LIST:
(all items within each tier are listed in order of greatness)

S tier = Fire Flower, Airplane
A tier = Heart, Mushroom, Boat
B tier = Mario, Star, Game Boy, Car
C tier = Swan, Pig, Baby, Yoshi
D tier = Dog
Trash tier = Cat

pretty legit tier list, i'm inspired to do my own now which isn't too different--

S tier: Heart, Airplane (these are perhaps the only truly good sounds although the tuning on the plane is unfortunate)
A tier: Car, Fire Flower, Mario (all of these have good, solid utility)
B tier: Game Boy, Boat, Mushroom (situational but quite valid)
C tier: Swan, Cat, Star (niche but usable)
D tier: Dog (underwhelming tonally which ranks it lower than Cat)
Trash tier: Yoshi, Pig, Baby (borderline unusable for anything but hee hee sfx)

also i like how you managed to make a mario paint entry that still sounds like "your music" - i could tell from the rhythm at the beginning like immediately. that's impressive in a way lol.

Better a groan of recognition than a blank stare of facelessness, I suppose.

I think Airplane is the only sound that could exclusively carry an entire song without it coming across as "ah, this clearly must be a one-instrument challenge bitpack". In that context especially, the tuning isn't so critical, since it has only itself for reference.

Dog is definitely weak, way too quiet and probably the most bland sound of them all, but what keeps it a hair above Cat in my book is the fact that Cat clips in at the start.

I may have ranked Pig a bit too high, honestly. Pig's utility is in layering it with percussion instruments. You can get some cool effects, but it's still marginal, especially with the limited polyphony available. It also clips out even worse than Cat clips in.

Baby and Yoshi are okay for "punctuation" (the "Mushroom" song in Mario Paint is a good example), but yeah, they're extremely limited-utility. I rank Baby a hair higher because Yoshi is just so recognizable it's impossible to convey anything other than "ah, yes, Yoshi, the classic meme sound".