I am in the process of knitting a neon yellow and pink tea cosy for my Etsy store. It should be up soon!
In the meantime, I stumbled upon these cup cozies from The Cozy Project on Etsy.
Seems like a great way to be more eco friendly when ordering a cup of joe. I have also been thinking about getting back into crochet for some time now. I haven't done it since high school, but making a cup cozy would be the perfect project to get back into it.
Here is a free pattern for a mug cozy by Lauren Frank, found on Ravelry:
I also love this knitted cup cozy by Kara L. Mayfield (pattern for purchase on Ravelry):