There's growing interest in baby blankets that are breathable. It makes sense to reduce the chance of impaired breathing if baby gets wrapped up in a blanket. Some say not to use a blanket (or any bedding material) before 12 months, but others see that as extreme and instead opt for breathable baby blankets.
We've also see the term holey blankets as well as cellular baby blanket, defined on one site as follows:
A cellular blanket is a lightweight cotton blanket which contains lots of small holes, or cells. These holes are essential for maintaining airflow and helping to keep baby at the right temperature unlike tightly woven thick blankets which may cause overheating.
To us the point isn't whether or how much cotton there is, but that it is lightweight and breathable. In fact:
A hand-knitted blanket is just as breathable as a cotton-based cellular blanket.
Think about the knitted hats and scarves you've worn - perhaps made by your grandmother. As you can see in the image here, there is space between each strand of yarn, and even more so when it is stretched a little - plenty of space for air to pass. A safe blanket.
Many of our knitted blankets are cotton-based, so they are essentially cellular cotton blankets and there is no conflict at all. The problem is that the baby blanket world revolves around factory-made fabrics that are cut from rolls to make baby blankets. We're just not into that.
If breathability is a top concern of yours, we recommend a lightweight knitted baby blanket. It's really just another form of cellular baby blanket. But...
it's never seen the inside of a factory
Here are our most lightweight knitted breathable baby blankets. And FYI the yarns have from 45% to 100% -- you guessed it -- cotton!