An example: Mordacai/Zero/Aurelia would be a sniping preferred play style.
Here is mine:
Borderlands 1 - Mordacai
Borderlands 2 - Salvador
Borderlands: The Pre-Sequel - Nisha
Pretty obvious if you ask me, but go ahead and guess my preferred play style
You play whatever is the most OP, but primarily gun-based over things like explosive, action skill, etc.
My second guess is just Pistol love, just because if you had no idea how OP Sal was you’d probably look at a skill like Huckleberry and be like this guy is a pistol guy.
But sure I’ll bite (I’ll go by the thing I first played with regardless of how many characters I have).
Mordy - Sal - Willy
In BL1, currently, my main is Lilith, at 69.
Merc COM with SMG Ammo Regen and damage.
Wuth
Aside from a Mordy at 13, she is my only BL1 character. I got a late start…
In BL2, either ammo eating Gunzerking Sal or left hand and middle skill melee / slag / DPUH / Fire Hide of Terramorphous Krieg with a Seraph relic that boosts melee damage and action skill cool down time.
In TPS, my playstyle used to be elemental lasers / Bulwark / 3DDIE but, has evolved to cryo/explosive with Shock for backup.
My main would be Aurelia (first to solo TPS with and my only 60+ toon), but i have an Explosive / cryo Too Scoops / Fatale / shock laser / Flakker or Fragnum or Jakobs shottie Avalanche shield cryo or voltaic strafing run Oz kit with SWAB/OLT and he is devastating, currently at 54.
Although i really play Aurelia and Clappy much the same way.
Back in my laser days, CS Athena (53 right now) was my main.
lillith bl1
maya b2
nisha tps
try to guess my play style
Oh i guess i didnt fully understand the concept of this thread lol…
BL2: Sal, Axton, Maya, Krieg, Gaige (No Zer0, sorry)
TPS: All of them
If you guessed guns and shooting things and collecting loot, you are correct.
You are funny!
BL1: Roland
BL2: Axton
BLTPS: Wilhelm
Mine seems obvious…
Borderlands 1 - Mordecai
Borderlands 2 - Zer0
Borderlands: The Pre-Sequel - Wilhelm
Your’s is a tough one btw. Mordy can be either long or short range, sal can be tank or short range, while Wilhelm can be anything really. No idea!
BL1: Mordi (used to be Lilith)
BL2: Gaige
BLTPS: Athena
The fact that I did post about Lilith should give a clue, I think.
As for yours, I would guess that they all pretty much “live for the kill” so to speak.
Yay, Amon Amarth reference!
I don’t have a true main since I play as every character, so I’ll list my favorite instead.
BL1 - Lilith
BL2 - Krieg
TPS - Nisha
Lilith, Zer0, Athena.
All got great Melee and their action skill helps you avoid damage, either by being invincible, invisible or both.
BL1 Mordacai
BL2 Gaige
TPS Fragtrap
Trukr, likes character dialog and minions. What is not too like about that! 
BL1 - got it a month ago … still need to play
BL2 - Krieg
TPS - Timmothy
Axton
Roland
Athena
Main? As in, one character I prefer more than others? I literally hold the down arrow key at the character selection screen so the selection reticle scrolls through the characters, I look away from the screen, and randomly let go for my decision (sometimes I ask my wife to say, “when”). In BL2, where I have two of each, if I land on ‘create new x’, then I play the less-recently played x character. That said, there are single characters from each franchise that I don’t play, so maybe that will answer this question:
BL1 - Brick (melee/punch wasn’t my thing, and his focus on rocket launchers was a turn off, since they seem unusually weak in that game)
BL2 - Krieg (with Salvador a close second even though I ran that ding dong to OP8)
TPS - Jack (not enough items in his skill trees pique my interest, but I may warm to this character with time).
Mordecai (Assassin)
Axton (Grenadier)
Claptrap (Sapper)
yayyyy
edit: added COMs because why not