A roster of 10 characters only?! Create it!

[Makaioshin]

1. Kid Goku
2. Kid Kuririn
3. Kid Vegeta (Raditz assist)
4. Kid Gohan
5. Kid Trunks (Goten assist)
6. Kid ChiChi
7. Kid Shin

Secret characters
8. Arale
9. Kid Jiren
10. Gomasu (Dragon Ball Fusions)

This would truly be an incredible game based off recent events.

[SonTao]

Ooooh, let`s see....

Honestly? I`d love a Dragon Ball fighting game, with a little twist!

1 - Kid Goku
2 - Kid Krillin
3 - Master Roshi
4 - Yamcha
5 - Tenshinhan
6 - Chaotzu
7 - Chi Chi
8 - Grandpa Gohan
9 - Tao Pai Pai
10 - Demon King Piccolo

But, as a bonus "what-if", Goku gets a super-saiyan transformation when you complete the game, with a what-if-cutscene showing when it happened!

Dude, this sounds so sick! But I feel like you could do something with Tenshinhan having Chiaotzu act as a part of his moveset to kinda cut down on the characters--unfortunately Chiaotzu is kind of a dinky little guy. Instead, I raise you...

Kid Raditz (Secret Unlock)

Building on your what if scenario a bit. Like in the Supersonic Warriors, it can be like how there are story modes that change based on who's perspective you're playing in! Kid Raditz shows up way earlier than in canon, and forces Goku to come down from Kami's Lookout mid-training to join up with his pals and take on Kid Raditz. Kid Goku's ultimates in this scenario include Kid Goku's SSJ state.

Considering the new Daima series that was announced, a game with this kind of a roster might not be so farfetched.

Shoot, you're right. Completely forgot that was announced. Slight off topic, but what did you think of Goku's new gi?

[Almighty Majin]

Dragon Ball

Spoiler:

1. Goku (Kid)
2. Krillin (Kid)
3. Tien
4. Yamcha
5. Master Roshi
6. Emperor Pilaf
7. General Blue
8. Tao Pai Pai
9. Tambourine
10. King Piccolo

Dragon Ball Z

Spoiler:

1. Goku
2. Vegeta
3. Gohan
4. Piccolo
5. Gotenks
6. Future Trunks
7. Krillin
8. Freeza
9. Cell
10. Buu

Dragon Ball Super

Spoiler:

1. Goku
2. Vegeta
3. Gohan
4. Piccolo
5. Broly
6. Future Trunks
7. Freeza
8. Goku Black
9. Jiren
10. Gamma 1 & Gamma 2

Dragon Ball GT

Spoiler:

1. Goku (Kid)
2. Vegeta
3. Trunks
4. Pan
5. Uub
6. General Rilldo
7. Bebi Vegeta
8. Super 17
9. Nuova Shenron
10. Syn Shenron

Dragon Ball Heroes

Spoiler:

1. Goku
2. Vegeta
3. Xeno Goku
4. Xeno Vegeta
5. Xeno Trunks
6. Cumber
7. Hearts
8. Fu
9. Aeos
10. Ozotto

[Kaboom]

Okay, I'm going to kinda go Hard Mode and try to make a franchise-spanning "all-stars" roster of only 10 characters. But I'm gonna cheat a little bit by having alternate outfits to represent different variants of those characters... and then I'm gonna cheat even more by adding a few potential "unlockable" bonus characters.

• 1. Son Goku (Child) [Outfits: Standard DB Orange, GT Blue]. His ultimate move is the full-power piercing punch used to defeat King Piccolo. In the GT outfit, it becomes the Dragon Fist.
• 2. Son Goku (Adult) [Outfits: Standard Z Orange, RF Orange, GT Blue]: His ultimate is the Super/x10 Kamehameha, performed while briefly transforming into either Super Saiyan, Super Saiyan Blue, or Super Saiyan 4, depending on the outfit chosen.
• 3. Piccolo [Outfits: Standard Z, Demon King]: His ultimate is the Makankosappo in the standard outfit, and the city-destroying "Explosive Wave" or whatever you wanna call it in the Demon King outfit. But it's just a cosmetic difference and the gameplay effects are the same.
• 4. Son Gohan (Ultimate) [Outfits: Standard Z Orange, Piccolo Purple, Great Saiyaman]: His Ultimate-powered ultimate is a melee rush based on his beatdown of Evil Boo. While using the Saiyaman outfit, the camera angles are more dramatic and there are some very noticeable sentai-style explosions in the background.
• 5. Vegeta [Outfits: Standard Z Armor, RF Armor, GT Not-Armor]: His ultimate is the Super Gallic Gun, and like Goku he goes SS1, SSB, or SS4 to perform it depending on the chosen outfit. When the GT outfit is selected, there's a slight chance of him appearing as Baby-Vegeta instead, which will cause him to power up to his "Super Baby 2" form for the ultimate.
• 6. Freeza (True Form) [Outfits: Standard, Coola]: Yes, I'm shamelessly sneaking in Coola as an alternate "outfit" for Freeza. They both have the same voice and the same big-ass Supernova attack as their ultimate. Freeza goes Golden while performing it, while "Coola" goes into his own Super form instead.
• 7. Perfect Cell [Outfits: Standard Green, "Max" Red]: As much as I hate halfway including anything from Super Hero in this, the red color scheme makes sense now for a simple alternate "outfit" for Cell. His ultimate would just be a big-ass Super Kamehameha, I guess. When defeated, he has a 10% chance of auto-reviving with 1 restored health bar and a damage boost.
• 8. Majin Boo (Fat) [Outfits: Standard, GT Oob, Neko Gi]: The alternate outfits are obvious homages to post-merger GT Oob and Neko Majin Z, with Boo still wearing his own gloves and cape on top of them. His ultimate in all three outfits is the Candy Beam, though in the Oob outfit he fires it from his hand instead of his antenna.
• 9. Broli [Outfits: Standard Z, DBS]: Z Broli fights in his "restrained" Super Saiyan state from his debut movie and nuBroli fights in his Ape-powered "Rage" state, but their actual gameplay is identical. For their ultimate, they both go Legendary Super Saiyan and deliver a melee rush ending in a big close-up ki blast.
• 10. Beerus [Outfits: Standard, Champa colors]: His alternate outfit is just a cosmetic homage to his brother, and his ultimate attack is... I dunno, his big planet-destroyer energy ball thing, I guess. Who cares. When playing as Adult Goku (Z outit) against him, Goku will go Super Saiyan God for his ultimate attack instead of regular Super Saiyan.

And now for the bonus characters...

• 11. Arale [Outfits: Standard, Kame Gi]: For her ultimate, she fires a giant mouth-beam as the Gatchans jump in and add to it with their antenna beams. While using the Kame Gi outfit, Kid Goku also jumps in and contributes a Kamehameha, though gameplay-wise the damage doesn't change.
• 12. Bardock [Outfits: Standard Z, Tullece Purple]: Fuck Minus and Super's bullshit, we're sticking with the real Bardock. His alternate outfit is just an armor palette-swap with Tullece's colors instead of his own. His ultimate is a melee rush ending in the blast attack he threw at Freeza, and he has a 20% chance of going Super Saiyan while performing it and dealing extra damage.
• 13. Vegetto/Gogeta [Outfits: Standard Z (Both), Xeno (Vegetto), DBS Blue (Gogeta)]: They share a single character slot, and which one of them you get is chosen at random at the onset of the match. Vegetto's ultimate is the Final Kamehameha and Gogeta's is the Big Bang Kamehameha, but gameplay-wise both have the same effect. The form they take (SS1, SSB, or SS4) while performing the ultimate is likewise chosen at random.

[ZombieVito]

1.- Ultra Instinct Goku.
2.- Super Saiyan Blue Evolved Vegeta.
3.- Beast Gohan.
4.- Orange Piccolo.
5.- Super Saiyan Full Power Broly.
6.- Beerus.
7.- Golden Freeza.
8.- Hit.
9.- Fused Zamasu.
10.- Jiren.

[Hellspawn28]

A roster of 10 for DBGT.

Black Star-Baby Saga:

Kid Goku
Pan
Trunks
Goten
Gohan
Uub
Ledgic
General Rildo
Baby Vegeta
SSj4 Goku

Super17-Shadow Dragon Saga:
Kid Goku
SSj4 Goku
SSj4 Vegeta
Pan
Cell
Freeza
Super 17
Si Xing Long (Nuova Shneron)
Super Yi Xing Long (Omega Shenron)
SSj4 Gogeta