We recently moved to our own mail server because working with Amazon was untenable. I don’t envy anyone who has to work with them. Anyway, current companies blocking our mail are:
t-online.de (you wouldn’t believe the craziness this company demands of email senders)
yahoo (includes sky.com, yahoo.sg, yahoo.tw, yahoo.gr, aol.com)
All other companies have modern email policies that check SPF records, rDNS, FCrDNS, DKIM, DMARC, etc… in which we pass perfectly.