I started seeds in red solo cups labeled with a sharpie. When they went out to the garden, I cut the side with the info and stuck it in the ground. So far, so good. No fading ink and the red makes it easy to spot.
I found some awesome artistic wooden garden markers that hang by a sturdy stainless steel stake on Amazon Handmade. They are laser cut and engraved and I can't wait to try them! I attached an example of one of them. There are 50 in the box I got!