FLAN-T5 is a finetuned version of Google's popular T5 model with instruct-finetuning. As stated in the model repository's introduction, compared to T5, FLAN-T5 is "just better at everything." With its permissive license, FLAN-T5 has become a popular option for a starting instruct model.
WizardLM is a variant of LLaMA trained with complex instructions.
WizardLM is a LLM based on LLaMA trained using a new method, called Evol-Instruct, on complex instruction data. By using AI to "evolve" instructions, WizardLM outperforms similar LLaMA-based LLMs trained on simpler instruction data. On the 6th of July, 2023, WizardLM V1.1 was released with significantly improved performance, and as of 15 April 2024, WizardLM-2 was released with state-of-the-art performance.
Further reading