Imperial Dragon the Primoredial Dragon
Full art:

Source.

Centur-Ion Primera Primus
Full art:

“Its arms and legs are longer than when in human form”

Source.

Dominus Impulse
Full art:

Spirit Princess:

“A water-like elemental. Depending on her mood, the liquid around her turns poisonous and viscous. Her wings are made out of a water [membrane/film] (she can use them to fly)”

Summoned Beast:

[Size comparison] “About this much”

TL note: The word used for the dragon-like creature is 召喚獣 (shoukanjuu, summon-beast), which is the same word used for the “Invoked” Fusions.

Source.