Spright Support
This Aqua-type level 2 can easily Special Summon itself out of the GY by banishing a Frog from your GY. It is also Des Frog while on the field.
Ronintoadin
1
Tearlaments Kitkallos
Arguably the best deck of all time, it would frequently mill a majority of both player's decks.
Tear Ishizu
One of the new Ishizu support cards, infamous for the funny MBT clip.
Agido the Ancient Sentinel
This character gives Yuma the key that contains Astral
His Dad
This Aqua-type level 2 allows for easy fusion summoning when sent to the GY by a card effect. When Summoned, it does its best impression of Laundry Dragonmaid.
Tearlaments Merrli
2
Rescue-ACE Hydrant
A powerful Dragon-type deck that has had its flagship monsters banned for a very long time. Nowadays you see it used by Gage in the progression series.
Dragon Rulers
My favourite Level 2 Fire Attribute monster :)
Volcanic Scattershot
These 2 characters could be considered to be Yuma's rivals throughout the series.
Kite and Shark
This level 2 Fiend gives you a free draw when used as any type of material for an Extra Deck Summon, or for XYZ monsters just has to be detached as a material.
Capshell
3
Kurikara Divincarnate
The strongest Pendulum deck of all time, which utilised 3 different ARC-V archetypes.
PePe
One of the plantet that Visas visits, but not the Tear one
Pressured Planet Wraitsoth
The gimmick used in this series to play duels in real life is (e.g. 5Ds had Bikes, ARC-V is Action duels)
Duel Gazer - AR
This cheeky Sea-Serpent-type monster slides itself onto the opponent's field and gives you free information on your opponent's hand when used as link material.
Click & Echo
4
Slacker Magician
This spy themed deck was infamous for abusing the new Link mechanic and Firewall Dragon
Spyral
This unarthrodox inclusion has a great level and can destoy either face downs or Kaleidoheart to come from the GY. Woof Woof
Unchained Soul of Shyama
The chatacter Quattro uses this archetype
Gimmick Puppet
A level 2 Warrior who summons 2 more copies of itself when Special Summoned. Surely it will be broken one day.
Hero Kid
5
Ritual Beast Tamer Wen
The only good Ritual focused deck based of cosplaying different archetypes.
Nekroz
A Field Spell that stops Floowandereeze in its tracks... wait what do you mean thats a typo? I guess you're playing 2 copies of a Level 3 Zombie-type Fusion monster instead.
Zombie Warrior
The XYZ monster that is based on Yuma's transformation with Astral is...
Number S0: Utopic ZEXAL