The AI Models Index keeps tabs on premium releases from 15 top labs since 2023,...

https://stateofseo.com/how-do-i-cite-the-ai-models-index-october-4-2026-edition-properly/

The AI Models Index keeps tabs on premium releases from 15 top labs since 2023, with verified dates and blind-vote accuracy checks. Updated every two weeks, it shows a 56% improvement rate between GPT-5.1 and GPT-5