Joke of the day and large category of jokes accessible via REST API.
Jokes One API is a free Games & Comics API that requires apiKey authentication, is served over HTTPS and supports CORS, so it can be called from the browser.
Details from jokes.one.

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Geocode an address, validate an email, track a flight or pull stock data with one account, one dashboard and one API key.
The Jokes One API is provided by Jokes One (jokes.one).
Yes. The Jokes One API is listed in the Games & Comics category of the public-apis directory, which only includes APIs that are free or have a free tier. Check its documentation for rate limits and paid plans.
Yes. The Jokes One API uses apiKey authentication, so you need to register for credentials before making requests.
Yes. The Jokes One API supports CORS, so front-end JavaScript can call it directly.
Yes. The Jokes One API is served over HTTPS, so it's safe to use in production.