From SmashWiki, the Super Smash Bros. wiki
MarioIcon(SSBU).png This user is the oldest brother.
LuigiIcon(SSBU).png This user is a mama.
DrMarioIcon(SSBU).png This user stays away from apples
ToadIcon(SSBPM).jpg This user strongly hopes Toad is part of the post fighter pass DLC wave.
PeachIcon(SSBU).png This user thinks Princess Peach is the laziest Mario character development wise.
DaisyIcon(SSBU).png This user thinks making Daisy an Echo Fighter is questionable.
RosalinaIcon(SSBU).png This user doesn't like Rosalina's post-Galaxy 2 voices.
WarioIcon(SSBU).png This User is very serious about cleanliness and personal hygiene.
PiranhaPlantIcon(SSBU).png This user has never experienced save data corruptions.
BowserJrIcon(SSBU).png This user wants a Super Mario Sunshine sequel.
YoshiIcon(SSBU).png This user pays his taxes.
BowserIcon(SSBU).png This user thinks if your plans are constantly failing, maybe you should think ahead for once.
DonkeyKongIcon(SSBU).png This user has never played a DKC game, nor does he plan to.
DiddyKongIcon(SSBU).png This user thinks the mega banana in Double Dash should return in a later game.
KingKRoolIcon(SSBU).png This user thinks Mii costumes are offensive.
LinkIcon(SSBU).png This user thinks it sure is boring around here.
YoungLinkIcon(SSBU).png This user drinks a lot of strawberry milk.
ToonLinkIcon(SSBU).png This user has big eyes.
ZeldaIcon(SSBU).png This user is wise.
SheikIcon(SSBU).png This user didn't know Shiek was a woman until Super Smash Bros. for Wii U.
GanondorfIcon(SSBU).png This user is fast
PopoIcon(SSBU).png This user prefers cold weather over hot weather.
NanaIcon(SSBU).png This user almost always accidentally KOs Nana within the first 15 seconds of a match.
SamusIcon(SSBU).png This user seriously thought Samus was Captain Falcon in Melee, I am not kidding.
ZeroSuitSamusIcon(SSBU).png y can't this user crawl.
DarkSamusIcon(SSBU).png This user wonders if he's just a recolor.
RidleyIcon(SSBU).png This user is not too big.
KirbyIcon(SSBU).png This user doesn't pay his taxes.
KingDededeIcon(SSBU).png This user needs to clobber dat pink guy.
MetaKnightIcon(SSBB).png This user was broken, but got patched.
FoxIcon(SSBM).png FIYAH
FalcoIcon(SSBM).png This user likes bread.
WolfIcon(SSBU).png This user thinks you're good, but he's better.
NessIcon(SSBU).png This user wants to try strawberry tofu someday.
LucasIcon(SSBU).png This user got the mystical stick from the first Heftyhead encounter on his first Mother 3 playthrough.
CaptainFalconIcon(SSBU).png FALCONE PAWNCH!
PikachuIcon(SSBU).png This user managed evolve Pikachu without the use of a Thunderstone.
JigglypuffIcon(SSBU).png This user was never a fan of Jigglypuff.
PichuIcon(SSBU).png This user is no joke.
MewtwoIcon(SSBU).png This user cannot grasp the true form of Mewtwo's attack.
PokémonTrainerIcon(SSBU).png This user calls Gen 1's Pokemon Trainer "Ash", because he thinks the name "Red" sounds dumb.
SquirtleIcon(SSBU).png This user likes Squirtle a whole lot.
IvysaurIcon(SSBU).png Excluding Decidueye, this user thinks grass-type starters are underrated.
CharizardIcon(SSBU).png This user loves spamming wrap and fire spin in Gen 1.
TotodileIcon(SSBPM).jpg This user's favorite Johto starter is Cyndaquill. Sorry Totodile.
LucarioIcon(SSBU).png This user is the original, not the clone.
GreninjaIcon(SSBU).png This user greatly favors buffs over nerfs.
IncineroarIcon(SSBU).png This user chose Litten as his starter, and gave him an everstone as Torracat.
IceClimbersIcon(SSBM).png This user is wobbly.
MarthIcon(SSBM).png This user has magnet hands.
LucinaIcon(SSBU).png This user does not care about Fire Emblem.
RoyIcon(SSBM).png This user our man.
IkeIcon(SSBU).png This user fights for his friends.
RobinIcon(SSBU).png This user tipped the weight scales.
CorrinIcon(SSBU).png This user likes corrin-on-the-cob.
ChromIcon(SSBU).png This user is fine with more Fire Emblem characters as long as they don't have blue hair.
BylethIcon(SSBU).png This user thinks that yet another fe character makes the last fighter pass fighter feel so anticlimactic.
PitIcon(SSBU).png This user advertises for Staples.
PalutenaIcon(SSBU).png This user has a maniacal laugh.
DarkPitIcon(SSBU).png Ow the edge.
MrGame&WatchIcon(SSBU).png This user can't land smoothly with the L button.
OlimarIcon(SSBU).png This user respects Steve the trooper.
ROBIcon(SSBU).png This user thought R.O.B was just a Staff Ghost placeholder in Mario Kart DS.
LittleMacIcon(SSBU).png This user is good at recovering.
WiiFitTrainerIcon(SSBU).png This user is fit.
ShulkIcon(SSB4-U).png This user is really feeling the irritation if memes are overused, like dabbing.
DuckHuntIcon(SSBU).png This user does not like most dogs, but does like some breeds.
VillagerIcon(SSBU).png This user still plays Animal Crossing on the Gamecube.
IsabelleIcon(SSBU).png This user questions making Isabelle the mascot of Animal Crossing.
SnakeIcon(SSBU).png This user has bombs.
MegaManIcon(SSBU).png This user is scared of psychic kids.
Pac-ManIcon(SSBU).png This user is round.
SonicIcon(SSBU).png This user prefers watching tool assisted speedruns over actual speedruns.
RyuIcon(SSBU).png Think you can win with this user? Sure you can!
KenIcon(SSBU).png This user's got the hair.
CloudIcon(SSBU).png This user is the new Marth.
BayonettaIcon(SSBU).png If you want to learn why this user thinks Ultimate should've been T-rated, ask your mum.
InklingIcon(SSBU).png This user is a squid kid.
SimonIcon(SSBU).png It is said that this user is the brother of Alvin and Theodore Belmont.
RichterIcon(SSBU).png TAKE THIS
JokerIcon(SSBU).png This user is is looking cool.
HeroIcon(SSBU).png This user thinks universally banning Hero is just stupid.
Banjo&KazooieIcon(SSBU).png This user wishes he was never sold to Microsoft.
TerryIcon(SSBU).png This user mistook Terry for Jotaro Kujo at the reveal.
MiiSwordfighterIcon(SSBU).png This user has a sword,
MiiGunnerIcon(SSBU).png a gun,
MiiBrawlerIcon(SSBU).png and a pair of gloves.
Oliver.jpg This user loves cats.
AidanzapunkUserboxImage.png This user trusts and is a friend of Aidanzapunk.
SerpKing sig.png This user knows and kind of likes that one Serpent King guy. He kind of smells of old broccoli though...
PokemonMayNotAmused.png This user trusts and is a friend of Disaster Flare.
NessIcon(SSB).png This user enjoys Sugar. And Cookies. And PK Fire spams.
SuperSmashTurtlesUserboxIcon.png This user is a member of the Turtle Tribe.
S3AHAWK personal Userbox.jpg This random user reminds me of that S3AHAWK guy but they love to use Joker and wants to be with a team in Turf War *fistbumps*

Here's my userbox if anyone is interested

ST64UserboxIcon.png This user celebrates their racing victories with OmegαToαd64.