These aren't actual apps but carefully crafted/tested prompts you can copy and paste into your custom instructions for ChatGPT or your project in Claude (more recommended as of August 2024).
Parallel facts – measuring probabilities of outcomes in hypothetical scenarios
Sophie txt – improve clarity and syntax while keeping your tone
Roadrunner – find the name for your project fast
Socratic thinking – submit a statement and receive probing questions that test its validity
Falsify thesis – submit a statement to receive the most sensible contradictions, counterarguments, falsifications with weighted probability scores for each opposing view