All but one of my animals was shipped to me. To say it's commonplace is an understatement.
If you want something dark, you're looking at anery or charcoal, maybe caramel. I tried to aim for things that might give you decent project animals to work with or sell. So here's my question then... do you want a cool project you can continue working with or sell off, or do you just want to make a bunch of normals with basic hets just for the experience of trying out breeding? Because in literally any other animal hobby the latter is strongly discouraged. Frankly it annoys me that it's still no big deal in reptiles. It might be soon enough, though; the adopt-don't-shop movement already has a foothold in the UK.
I'm not saying this to be mean or discourage you, but we see a ridiculous number of posts (esp in Facebook groups) saying, "I put my red corn with my black corn and got all these brown babies. What are they?" and then they get rehomed for free into homes that may or may not take care of them properly, OR they end up stuck feeding 20 snakes they didn't anticipate keeping because the market is already oversaturated with unknown classics. The point I'm trying to make here is that if you're not contributing to the hobby by breeding, you might be contributing to the problem.
Now, if you want a darker colored female, charcoal is going to give you better het babies over anery, as blizzard corns are always popular but less common than snow. I can try to help you find a decent one if you'd like. They're certainly one of my favorite single-gene morphs, and I'm planning to work on darkening them further in the coming years.