I know exactly what you mean! This year I am using a paint pen but I want to get a label maker. I have the metal tags for in the beds but I can't read any of them anymore and I saw the tags with the label maker. Very nice! So maybe for next year. But then, you have to make them and USE them or it still doesn't work!
I have a tendency to think, I'll REMEMBER and I USUALLY DON'T! I always have lots of "mystery" plants. Guess that makes it interesting!
I did coleus seeds one year in a plug tray, carefully marked because I start seeds for my daughter also and she told me to make sure I labeled so we could tell the tall ones from the shorter ones. I DID. But I didn't have a sprayer and when I watered them, those tiny seeds just washed all over the tray! She was not happy!