Can anyone put together a list for the simplest to most complicated class in 13th age? I saw a list awhile back but no I can't find it anywhere and it's driving me completely crazy! Thanks so much!

Never played it.

The core rule book has them listed by complexity on page 75. If you don't have the book handy, here's the list from easiest to most complex:

Barbarian - for the player who just wants to roll dice and kill stuff without worrying about too many rules
Ranger - relies on base attacks augmented by a few class talents
Paladin - also relies on a short list of talents though, like the ranger, can be a little more involved if you choose certain talents
Fighter - simple to play but requires decision-making with regard to its flexible attacks
Cleric - easiest of the spellcasters
Sorcerer - more complex because of variant spells and the option to cast spells for double effect with more time
Rogue - more complex because you have to track your momentum and actively work to use Sneak Attacks effectively
Bard - lots of options including battle cries, spells, and songs
Wizard - about the same as the sorcerer unless you take the options that allow improvisation and ad-libbing

I can't recall all of the non-core classes and don't have any experience with them, but all the ones I can remember ranged from moderate to very high complexity. In particular, monks, druids, necromancers, and demonologists I would rate as very complex. The "leader" class (I can't recall the name right now) is probably around the fighter/cleric level. I believe there is also some errata that affects one or two of the classes, particularly the ranger.