Sentence examples for that I ever from inspiring English sources

The phrase "that I ever" is correct and can be used in written English.
It is often used to express surprise or disbelief about something. Here are two examples: - "That was the funniest joke that I ever heard!" (expressing surprise about the level of humor) - "I cannot believe that you would do something like that, the most selfish thing that I ever witnessed." (expressing disbelief or disappointment about someone's actions).