Any flags you own but don't fly?

I am writing a science fiction novel at present, set partly duting the Spanish Civil War. To get the feel of the different factions, I bought a 2nd Spanish Republic flag, both the crested and uncrested version, and the Francoist flag from 1945. For reasons that I trust are obvious, I'll never fly the latter. (I'm considering flying the 2nd Republic flag on 17th July, however I'm not blinkered to the genuine problematic histories of various factions on the Republican side.)

Are there any flags that you don't fly, but retain solely for their historical or creative value?