Styx songs that either sound like other Styx songs, or at least incorporate certain elements of other Styx songs.
I always thought "I'm Ok" sounded a little like "Fooling Yourself".
"High Time"/"This Time Next Year"
"Queen Of Spades"/"Suite Madame Blue"
"I Will Be Your Witness"/"Together"
"Save Me"/"I Heard It Through The Grapevine"(obviously not a Styx song, but certain musical parts: the transition between the chorus and verses on "Save Me", and then the little interlude after the chorus on "Grapevine" sound kind of similar. I wonder if DDY was paying tribute.