How to find suppliers/manufacturers to create a new branded product line?

[benwilliamson]

This is completely ignorant but I'm having trouble finding suppliers/manufacturers to help create (and manufacture) a new branded product line (let's say, hypothetically, a new athleisure line of clothes). I'm NOT looking to do drop-shipping, but rather to create a new line with someone who can make it. Are there sites or marketplaces to facilitate this? The ones I've looked at (Oberlo, Salehoo, etc.) seem to be focused on drop shipping. 

Thanks in advance!

[dropship_helps]

Hello @benwilliamson 

Please check printify and printful for the branded product line.