I second this. Most of the time I look for Japanese Onomatopoeias, I’ll find a website that will give maybe 20-30 examples, and then tell me to read manga to learn more.
For formal speech, Onomatopoeic words aren’t super important, but like 相槌、they really liven up casual conversation and make things fun. Having a deck dedicated to them so people can pick some up would be super cool to see.

さわさわぁー





