I’m assembling a small resource to evaluate and improve “idiomaticity” in LLM rewrites (outputs can be fluent but still feel literal).
For that, I’m looking for datasets of English idioms expressions with:

• idiom text (canonical form if possible)
• meaning
• example sentences
• ideally some frequency signal
• licensing that allows research

Questions

1. Are there any well-known public idiom corpora you’d recommend?
2. Any good frequency proxies you’ve used for idioms?
3. If you’ve built something similar: what fields ended up being most important?

If helpful, I can share the exact retrieval endpoint I’m using for testing — but mostly I’m looking for dataset pointers.