Hair powder and some of the other options mentioned cover gray hair temporarily, but you have to put it on every day or at least after you wash your hair.
Root spray is another well-known way to hide your roots. The best thing about it is that you can cover a lot of space quickly and easily.
You can also cover gray hair without a dye with hair mascara or a brush-on hair color. This is great if you only have a few white hairs.
A color stick or pencil is another way to make a quick fix. If you also use their touch-up spray, the one from Everpro is a good choice to try.