So, the ACT writing test has been redesigned as of September 2015, and the prompts now ask students to analyze an issue from multiple perspectives. I’m working with a student who is prepping for this test, and I haven’t been able to find many prompts. ACT has released two, which can be found here and here. Also, the site Magoosh has one here.
I’ve also made a couple more for my student. They’re not perfect, definitely too controversial for the ACT, but if you’re looking for more prompts you’re welcome to try them out: