>>1273787 Tohsaka Rin from Fate/Stay Night. The style suggests Fate/Ataraxia though, but in general, saying F/SN is a safe bet.
There is a doujin lingerie set for her. A fan like Casterday or Riderfan would probably be able to quote the name out of memory but they don't always seem to be around like they used to. Someone had also drawn Rin grown up as a woman sorceror and that was hot too although it wasn't strictly a panty-only drawing.
