With Brandstack gone (but possibly coming back), the alternatives are:

LogoGround
Exclusive logos
High quality
Pays 85% to the designer.

99Designs
Non-exclusive logos
High quality
Pays 30 – 50% to the designer, last time I checked.

LogoTurn
Exclusive logos
High quality
Pays ?% to the designer. Designers can’t sign up. It is by invitation only.

StockLogos
Exclusive logos
Average quality (in my subjective opinion)
Pays 75% to the designer.

And the winner is: LogoGround!

There are many others, but these are the four that I think are worth mentioning.

The only drawback of selling @ LogoGround is that about 9 out of 10 uploaded logos are declined. The focus is very much on quality. If you’re not an experienced designer, you might find StockLogos a less frustrating option.

Disclosure: As the founder of LogoGround I’m probably not 100% objective. Although, if it wasn’t my site, I’d still choose it based on the higher commission payout.