So, my goal was to compile every single official romanization used by Toriyama for proper nouns in the series. I believe I've achieved that goal, but would love to hear about anything I've missed!
Characters and other proper nouns are organized roughly in the order of their first appearance in the series. When I note the first appearance in the guide, however, I'm talking about the first appearance of that particular spelling, not when the character itself first appeared. So please don't get that confused.
In general, I'm just showing off the very first panel in which the spelling was featured, although sometimes I added an additional panel for clarity. Sometimes I also added some other notable appearances. Some of these spellings never appeared in the manga at all, but the sources are always noted.
I hope everyone finds this all as fascinating as I did! Also, if you're reading this, VegettoEX, feel free to shamelessly steal this for the main site/Wiki if you'd like!
CHARACTERS:
SON GOKUH
First appearance: 1987 tankōbon #06 - cover

Additional appearances (as simply "GOKUH")
Weekly Shōnen Jump 1989 #07 - cover

1990 "Akira Toriyama The World" - cover

Weekly Shōnen Jump 1990 #50 - cover

BULMA
First appearance: chapter 1

BLOOMERS
First appearance: Weekly Shōnen Jump 2007 #29 - concept image of the bonus figures included with the individual DVD release

Note: it's hard to make out depending on the quality of the particular scan you look at, but there does indeed appear to be a partially obscured letter s at the end.
KAME SENNIN
First appearance: Weekly Shōnen Jump 1987 #14 - promotional sticker set

Note: this is the only time I've ever seen Toriyama spell KAME SENNIN, although there is a ton of KAME in the series.
SHERMAN PRIEST
First appearance: chapter 5


Note: the father of one of Oolong's captive girls. Although not named in dialogue or any of the guide books, it's presumed this is supposed to be his name. As noted on the Kanzenshuu main website, his name "is most likely taken from the M4 Sherman and M7 Priest tanks used by the allies during World War II."
YAMCHA
First appearance: Weekly Shōnen Jump 1986 #05 - 1986 calendar

Additional appearance: Weekly Shōnen Jump 1989 #03/04 - 1989 calendar

PILAF
First appearance: chapter 135

KURIRIN
First appearance: chapter 166

KULILIN
First appearance: chapter 245


Additional appearance: chapter 328 - title page

栗 (kuri)
First appearance: chapter 125 - title page

Note: okay, this is actually more like the opposite of what this guide is focusing on, but I thought it was too cool not to note. Here, Goku's hoverbike and outfit display the 悟 (go) kanji associated with his given name, which is pretty normal for Dragon Ball.
Kuririn is likewise sporting the 栗 (kuri) kanji, which means "chestnut." As far as I can tell, this is the only time a kanji has ever been associated with his name! Perhaps his name could be written 栗林 in kanji? (林 is read either hayashi or rin depending on context, and it's used in the Chinese word "Shaolin," and by extention, the 多林 (ōrin) temple that Kuririn came from. So this is plausible. But I digress.)
LUNCH
First appearance: chapter 26 - title page


BLUE
First appearance: chapter 70


ARALE
First appearance: chapter 81

SLUMP
First appearance: chapter 82

TURBO
First appearance: chapter 82

YAJIROVE
First appearance: chapter 140, title page

SON GOHAN
First appearance: chapter 203, title page

Additional appearances:
1989 tankōbon #18 - cover

Weekly Shōnen Jump 1989 #36 - Jump Summer Festival (as simply "GOHAN")

1990 "Akira Toriyama The World Special" - cover

TRUNKS
First appearance: Dragon Ball Side Story - TRUNKS THE STORY - cover

Mr. SATAN
First appearance: chapter 394

BEEDEL
First appearance: chapter 440


Note: credit goes to SaiyaJedi for discovering this one years ago. Thanks, Julian!
JEWEL
First appearance: chapter 452


SON GOTEN
First appearance: chapter 518

Additional appearance: chapter 519 (as simply "GOTEN")

BARRY CARN
First appearance: chapter 476

Note: an extremely minor character. He's a famous actor appearing in SUPER GUY magazine (lol) that Majin Boo imitates to try and impress a girl for a kiss. This ends miserably. Barry also appeared in a Dragon Ball Super episode, playing the Great Saiyaman in a movie.
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OTHER PROPER NOUNS:
CAPSULE
First appearance: chapter 1


HOIPOI CAPSULE
First appearance: chapter 2

Note: this seems to be the only time "Hoipoi Capsule" was ever romanized in the manga. Eventually, Capsule items are consistently labeled CAPSULE CORP. and often include the iconic company emblem, as featured on Trunks's jacket.
In early chapters, there wasn't a standard, and the emblem didn't even make an appearance until around the Saiyan arc, as far as I can tell.
CAPSULE CO. LTD
First appearance: chapter 10 - title page

Note: this is the only time that I'm aware of the corporation being referred to this way. It's typically just labeled CAPSULE CORP.
It's also interesting to note that this is the first time Capsule Corporation itself is mentioned in the series. I don't think there's another reference until Goku travels to West City in the Red Ribbon Army arc, in chapter 68. Someone correct me if I'm wrong.
CAPSULE CORP.
First appearance: chapter 68

Note: this chapter is the first time Capsule Corporation is ever mentioned in dialogue, as far as I can tell. Here we see the standard CAPSULE CORP. making its first appearance, at Bulma's house.
It's also interesting to note the original Capsule Corporation emblem, featured on the entrance, which is a Hoipoi Capsule with the letter k inside.

The more iconic emblem with the letter c doesn't start to appear until around the Saiyan arc. The entrance has the updated emblem in later arcs, as seen below:

You can see he misspelled it as CUPSULE CORP. up top there. I saw this another time somewhere else in the manga, but I didn't find it notable enough to give it its own entry, so here you go.
Additional note: hilariously, during the Boo arc, starting with chapter 423, Toriyama went all the way back to chapter 68 to reuse this exact same establishing shot! It's used multiple times. You can even see that the cars and airplanes are the same. This creates a slight continuity error, because the old Capsule Corporation emblem is featured on the front entrance, instead of the newer one.

Toriyama sure was at his absolute laziest at this point in the series!
CAPSULE CORPORATION

KAME HOUSE
First appearance: chapter 12

RED RIBBON
First appearance: chapter 155

Note: this henchman has a jacket which says RED RIBBON on the back. Quite infamously, later appearances on other items seem to always say RED RIBON instead.
I'm using the kanzenban as a reference; can anyone confirm that this also appears as RED RIBBON in the magazine run and the tankōbon run? It's possible that this was originally misspelled RED RIBON and later corrected. Maybe they just decided it wasn't worth the effort to correct the misspelling for the remainder of the chapters.
Additional appearance: 2003 Kanzenban #7 cover

RED RIBON
First appearance: chapter 70

Note: from chapter 70 onward, I could only ever find the spelling RED RIBON.
SAIYA
First appearance: Weekly Shōnen Jump 1991 #33 - cover

Note: this is the only time I've ever seen this spelled by Toriyama in alphabet.
WE-KONG HOSPITAL
First appearance: chapter 243

Note: this is obviously a reference to Sun Wukong, the inspiration for Son Goku. Of course, it seems to say WE instead of WU and there seems to be space for another letter. Perhaps it's supposed to be WEUKONG HOSPITAL? That's not a standard romanization, but it works. I guess we'll never know exactly what it's called, but I thought it was interesting to highlight.
SATAN CITY
First appearance: chapter 421

SATAN CITY POLICE DEPT.
First appearance: Weekly Shōnen Jump 1993 #45 - insert poster calendar

ORANGE STAR HIGH SCHOOL
First appearance: chapter 421






