The poster child is the Trilithon.
The trilithon may be your poster child as spoilia but where is the evidence that it was used in another place for another purpose as per the meaning?
"Spolia (Latin, 'spoils') is the re-use of earlier building material or decorative sculpture on new monuments."
Judging from the still-to-be-used stones in the Baalbek quarry, it would appear that, at some time, construction was interrupted at this site and restarted, most probably, by the Romans. The trilithon served as a base for further work.
Who were the original builders? Some say the Romans. Other say that Baalbek is a legacy of an earlier civilization.
Just saying, "I believe there is evidence all around us," doesn't make it so.
You need to provide this evidence or simply be dismissed.