The search continues.
Here is my dossier of potentially breathable exoterras.
Of about 2 dozen otherwise habitable planets except for levels of CO2
which are too high, I've found about 5 planets in the Milky Way which are (probably, correct me if I'm wrong) habitable.
If I understand correctly as well, some of these terras would have the effect of heightening mental functioning through higher levels of oxygen
A thin atmosphere and a long day on this one.
This one has a pretty thin atmo as well, though its appearance is exotic. Is this the "Barbie World" they talk about?
This one is, afaik, habitable if not a little cold. But put a coat on and you'll be fine.
And though this ones rotation is very slow, if you could work out a way to get around that you'd be living on a pretty beautiful planet. I love those 'whispy' landmasses and the comfortable and height-conducive 0.6g environment.
Oh - the pictures attached in a weird way. Whatever, too tired to sort it out lol. The pics at the bottom are in the right order.