Good resources for expressions and colloqialisms?

Not sure exactly what you are looking for or want to express but check out the collected resource guide here. If you are a beginner, I imagine most the of physical textbooks have decent starting point for conversation expressions along with associated audio.

The Ultimate Additional Japanese Resources List!

This is a book for common expressions that are not typically taught in textbooks. I’d put it at an intermediate level but some stuff is well know just from natural exposure from vocab. It’s got a lot of good stuff (along with audio samples) that definitely comes up in media along but probably not suited for immediate conversation needs.

I don’t have this but I’ve been wanting to check it out since it’s from the same author as the dictionary series and looks quite thorough at +700 pages of metaphors. I’ll post it again to see if anyone has it because I’d like to hear their impression. Here is a sample link. It seems more advanced but probably a great resource for smoothing out translations.

What has helped me in expression is writing and have native tutors check it. You can start with self intro and personal story, interests or just general talking points. With writing, we have the time to experiment with more complex expressions/grammar and sort have a basic script to work with so you can improvise better within conversation. I’ve seen other get stuck on expression by being too literal with their native thoughts and wanting to express it (but can’t) so practicing on consolidating and simplifying has helped greatly but it’s usually through natives that have helped best in this respect.