Just some speculation I've done with regards to potential Ultimate forms, because to some extent just speculating and theory crafting is fun, as an aside I also include varients in this so please don't bug me about which variation would be better or not.
Likely Ultimate's: Ultimate mon that I think Verge is likley to become for one reason or another.
GrapLeomon
Why: It's both a natural evolution of Gryzmon and fits with Verge's current personality.
Powers: Good usage of wind abilities, good fighting skills.
Others: Unfortunately and like many of Verge's potential Ultimates it is not fluffy.
Mach Gaogamon
Why: Much like GrapLeomon it is a good fighter, in addition Verge has just shown off a sonic attack adding points in it's favor.
Powers: Good fighting abilities and some sound based powers.
Were Garurumon
Why: Like many of the likley options it appears to be a fighting focused Mammal Ultimate and it is described as being loyal something I feel pits Verge's devoted nature very well.
Powers: Third verse same as the first.
Garudamon
Why: It's X version is a natural evolution and seems to have a fitting personality for a hero.
Powers: Flight, the same fighting abilities as the above three.
Vjramon
Why: A combat focused deva this guy has many of the benefits the above mon two but is also good with magic to match Verge's own proficiency in the area, in addition among the mentioned mon this one is explicitly mentioned as having an honorable personality, though it's supposed 'detachment' is a big mark against it I don't seen it as enough to bump it down with everything else going for it.
Powers: Strong and a deva giving it good magic as well.
Other: Actually looking at the detamchment it mentions that as an aim and not as a personality trait in of itself making this seem more likley, if any mon where to become more likley due to the Dark Purple text I think this one could be it.
Confused: As a Centaur like digimon Verge's bipedal mutation may make this guy less likely.
Mammon
Why: A natural evolution.
Powers: Fairly strong and apparently adds very good sight and hearing to Verge's list.... we'd basically be a detector character in this form if we kept our sense of smell.
Monzaemon (Panda and evil versions included for convience sake)
Why: It's a natural evolution of Verge's current form and could fit with the kind side of his personality.
Powers: It's adorable and that's all it needs, one of the few Sublimates the retains Verge's huggability.
Flaremon
Why: It's a powerful fighting focused mammal Ultimate whose emphasis on heroic deeds reference Flamemons ideals and whose potential membership in the Olympus 12 references our sibling relationship with Luna.
Powers: It's an action anime protagonist basically.
Andiramon
Why: Though it's data type is off and so far is the only one in this teir that's not a normal Gryzmon evolution it is both a physical fighter and a magic user much like Vjramon above it. However due to it's description as having a 'kind' personality I feel like these aspects would line up with Verge more.
Powers: Apparently pretty darn brutal when angered, otherwise it's got the deva package.
Reasonable: Mon I feel like we can reasonable assume that Verge is capible of becoming but aren't quite as likley as the others.
Caturamon
Why: Natural evoluton with a Justice focus, however it is
ugly with Verge's painjob and is relegated to this tier because of it.
Powers: It's a deva what do you think?
Loader Leomon
Why: It's a mammal digimon with a talen for digging and spinning attacks in reference to Verge's Rookie form.
Powers: Its pretty much an digging machine weather that be through stone or other mon.
Other: Getting this would likley either involve Verge's Rookie form or regaining his love for digging.
Cerberumon
Why: A duel Vaccine/Virus mon like Verge himself.
Powers: Very strong close claws that are likley to be further enhanced by Verge's nature, also a Gate user which is always scary.
Panjyamon
Why: Mammel evolution.
Powers: Basically a Leomon with ice powers.
Rapidmon
Why: A mammal based Ulimate, though one that's also machine based,
Powers: Missiles!
Notes: We can become kaiju eventually if we do this right... letz dooo eeeet!
Zudomon
Why: It's a mammal based humaniod Ultimate.
Powers: It has a hammer!.... and that's all anything really needs so far as power is concerned.
Tylilinmon
Why: It's fits the requirements of being a mammal Ulimate and like Verge it really hates senseless killing.... the only reason it isn't higher because Verge's current form is a bit of a blood knight and because it a bit on the op side.
Powers: Very powerful for an Ultimate.
Vikaralamon
Why: It is a large digimon, has powerful magic, has good support opportunities, sleeps much like Verge's bear form, is swoll like Verge, has a gentle personality, and while the profile might not indicate it Boars are freaking savage when you make them angry which I feel fits Verge perfectly.
Powers: Very powerful physically and has MAAAAGIC!.... like most deva actually.
Other: Hey.... if we become the turtle sovergn at some point in the quest would that make us digimon Gamora?
Notes: Can you tell I want this guy yet, because I do.
Mihiramon
Why: Apparently replaces Centuramon in our currently evolution tree and as a result probably gets all of the traits that would have put in this teir if it wasn't so ugly. However it's personality leaves me skeptical.
Powers: Deva also it can fly!
Kaiser Leomon
Why: It's a mammal Ultimate.
Powers: It's an Ultimate level LW with all that entails.
Garumon
Why: Another mammal Ulimate this one has the additional bonus of a just peronsality.
Powers: Ultimate Legendary Warrior, thats really all that needs to be said.
Gokuwamon
Why It's a fighting focused humaniod mammal digimon.
Powers: Good fighting, thunder powers, and flight a pretty good package all things considered.
Theories: Mon that I can see Verge becoming for a variety of reasons, but either are reliant on unconfirmed rumors, are extremely unlikely, or are mon we flat out don't want to be for one reason or another.
Cyberdramon
Why: Because it's a natural evolution of Gryzmon, however it not being a mammal based digimon knocks it down a few tiers in my books with Drex's statements.
Power: Actually very strong and has a potential instant kill attack in Erase Claw.
Other: This guys seem fairly unstable which when combined with their unlikely nature makes me put down in this category.
Jijimon
Why: It's a mammal based Ultimate and in Digimon is often seen as a caretaker for a village... in all honestly I think I
Powers: It's actually pretty darn strong and seems to have a Heaven's Gate lit attack with a built in IFF with its 'Hang on Death' attac.
Indaramon
Why: Mammal ultimate with powerful magic, it's so low because of it's $%@$! personality which ironically puts it at odds with one of my top choices for possible evolution.
Powers: Standard deva package plus sonic attack.
Callismon
Why: Though it is a mega it is something that a Gryzmon can directly become though I feel it unlikely.... though the data from beyond 'The Gate' could be Arkadiamons I don't think it's likley and even if it is I doubt it's going to fire off while Verge is still a Champion.
Powers: It's a freaking mega of course it's scary strong!
Kyukimon
Why: Another mammal Ultimate this one is lower because of stat differences, but it does have wind attacks which Verge has recently used.
Powers: The power of wind!
Delumon
Why: Natural evolution but otherwise doesn't fit Verge in the least.
Powers: Why is this thing even on this list?
Knightmon/
Mistymon
Why: Influence from Yiggy for the former and all that data from scratch for the later I don't really want either of these personality.
Powers: Melee focused fighters one of which is better at magic....eh.
Mad Leomon
Why: Possible Dark Digivolution....do....not....want.
Powers: RAAAAAAAAGH!
Skull Baluchimon
Why: Possible Dark Digivolution.... really do not want.
Powers: Appears to have a lot of creepy fear based powers, and is creepy.
DORUguremon
Why: Mammal Ulimate though Dex has mentioned personality conflicts.
Powers: Fairly strong.
Andromon
Why: Yiggies influence, Verge's metallic parts, as well as the fact the that that Royal Knight whose skill Verge used is Craniumon.... surprisingly enough Adromons evolution tree ends in Craniumon. Also Andromon is just cool, I don't normally like getting more human with digimon protagonists but this guy is cool enough that I don't care.
Powers: Apparently just under da hax vampires physically.... at night! Also have lots of weapons on it!
Other: Hey given our power we should totally get a trenchcoat and neat hat if we go this route... and then we can give to em!
Dinobeemon
Why: Natural evolution.
Powers: It exists.
Algomon
Why: It's a horrible mutant like Verge... I don't think it'll come about from anything good though.
Powers: A lot of stuff relating to manipulation of it's surroundings, pretty weird looking at it.
Anyway may or may not update this as things go... really tired now.