I'm a little biased - I like the seedbank I work for.

We have a special listing for high-yield seeds - a lot of them are for outside.

A lot of people like Big Bud - it's used by commercial growers. And, we have a Big Bud 2 coming in soon that's supposed have even higher yields than the original.

Critical Jack form DinaFem is good - 1450 gram yields according to the breeder.
Super Critical from Greenhouse has a 1200 gram yield.

We also have some mix packs for outdoor use that'll give you a sample from a specific breeder. Not sure where you're located, but if it's cool outside, our British Outdoor Mix by Feminised Seeds is pretty good.

Lot's more to choose from if you check out our high yielding strains

Of course, I'm looking at breeder info - If someone has some first-hand experience, go with that.