How are you defining it?
Beyond the usual "silly for silly's sake?"
Generally, post-1970s modernist buildings that dispense with the strict formality and lack of ornamentation of modernism and instead borrow heavily from classical or vernacular styles for ornamentation. Think columns and pediments.
Extensive use made of materials that aren't concrete and generally high-quality materials for cladding, quirky use of colour or other details. Think coloured bricks, marble, sandstone and bright metalwork.
Interiors often also of a matching high quality.
There isn't that much of it in Edinburgh, certainly not big examples, and most of it is pretty conservative by PoMo standards. The Gyle or the EICC are good examples. Leith Academy or Waterworld too (although not up to the usual defining budget and quality of materials)
I made a map that isn't complete by any stretch of the imagination; https://www.google.com/maps/d/edit?hl=en_US&app=mp&mid=1zKPqPBUIFeE4DYnJ2f9I5II0r8Y