Rainbow Sorcerer Help

[Potato disciple]

Hi guys!
Currently rolling up a new character for an upcoming campaign, and I need help on two things:
1) What bloodline is going to fit a rainbow oriented sorcerer? Fey seems like a decent choice flavor wise but the spells and abilities just don't fit the concept. There's a fantastic bloodline called hyperborean that's basically perfect but sadly it's 3pp.
2) What rainbow spells exsit other than the prismatics (spray, wall, sphere...), that are all very high level? Spells like disintegrate are also cool because the ray itself is colored (green in this case).
Thankies!

[The Sideromancer]

Firstly, bloodlines. You can get some extra light spells by going Solar. Protean gives you blur and disintegrate and could be adjusted to fit. Arial varint of Stormborn may work as well.

Spell-wise, I would run both Rainbow Pattern and Chains of Light as control spells, Mirror Image wouldn't be hard to refluff, and there's more niche attacks like Sunburst as well. Colour spray can work as well, but only because you're a sorcerer and can ignore the highly incorrect material component.

Of course, I have my own biases towards what is associated with light, and am obligated to include the Nanite and impossible bloodlines and the likes of molten orb and Iron Stake.

[Edymnion]

As for spells, always remember that YOU the spellcaster gets to describe how they look, as long as the mechanics remain the same.

You could do something like saying your caster traces out a rainbow, touches one of the colors on it, and then that color enlarges and produces the effect. So Cone of Cold could come from the blue band, Fireball could come from the red, etc.

You could Fly while leaving behind a rainbow trail. (https://www.youtube.com/watch?v=DCQrqexr0BI)

You could even do things like say Magic Weapon makes the weapon shine in rainbow colors.

Basically, take the spells you find useful, and then reflavor them to be rainbow themed. You're a Sorcerer, the magic comes from inside of you, its not learned from rigorous study and training. Long as it can still be identified as what it is via a spellcraft check, the sky is the limit.

[avr]

What Edymnion said, plus anything which creates something transparent - e.g. mage armor, aqueous orb, wall of force - can very easily split light into a rainbow.