I'm not professional, only doing open mics, and most of the audience seems to be 60-something like me. I do a couple by Terry Gilkyson, early 50's, pre-Elvis, and the comments I get are "I haven't heard that in years. Thanks". That goes for "Fast Freight" and " Greenfields". You didn't say who or where your audience was but "Haven't heard in ages" may be as good as obscure or not heard before. Instrumentally, Ebb Tide, Misty and The Girl From Ipanema seem to bring back memories for people and get me applause. I haven't hit them with any real classical yet but I might.
BTW, good that you're coming back after all those years.