How to validate white listing

Hi all,
Is there a way to check whether my email has been black listed? I’m disturbed by the number of times my clients who WANT email from me, tell me they found my communications in their spam folder. In early email blasting days, I remember my then-platform/service provider would get notification of a black listed account and had a way to assure our accounts are white listed. What’s the latest on this topic? Thanks!

Personally I like as my testing tool for that. Have you set your SPF and DKIM up as these will also make a difference.