There's this cool website that requires you to be a bit tech savvy, but is amazing for booking lightning lanes. I used it at DisneyWorld in January, and Disneyland last week, and works an absolute peach.

Disney drops extra lightning lanes throughout the day based on crowds and usage. For example, the app may show the next lightning lane for a particular ride is available in 6 hours, but then a small batch will be released for immediate use that get gobbled up before anyone can see them. This website allows you to see and book those drops right in the website. It essentially taps into Disney's lightning lane API, and tells you when lightning lanes are about to drop. It is incredibly useful, and I was able to book lightning lanes almost one right after the other. The only limitations are you can only use one lightning lane per attraction per day. Last week, we ended up using all of them each day by early afternoon. It was amazing at DisneyWorld too.

This process requires a bit of tech savvy and serves as a decent barrier to too many people using it. Also, it seems Disney knows about this for over a year and has not turned off that opening in the API.