Which teeth whitening product is good?

I am looking into teeth whitening products due to tooth discoloration.

Whitening toothpaste has mixed reviews, and I'm looking into over-the-counter whitening products that are claimed to be effective.

Whitening patches, sticks, gels, machines, and other types are more numerous than I expected.

Do you have any whitening products you've tried that showed effective results? Please recommend them~~