The color of your boogers when you're not sick with a cold, flu or other infection should be a white clear color.
When you're healthy you still can produce boogers and need to blow your nose and as long as your boogers are a clear white looking color then it's normal.
Sometimes during winter when the air is dry you may also see a bit of blood in your boogers which is also normal and nothing to worry about.
You have tiny blood vessels in your nose and those tiny blood vessels can easily crack and cause nose bleeds which can either cause blood to come out of your nose or even just cause a little bit of blood to be in your boogers.
It's normal and adding humidity to your house can help prevent those nosebleeds.
If your boogers change color such as turning yellow, green etc then you likely have a cold or other infection.
However a dim yellow color of boogers is normal but a darker yellow color can be a sign of infection.
Black and or gray colored boogers can mean you're breathing in pollution such as dust.