What Ink do you use in a vintage fountain pen?

I just took a survey of ink in my home office area and found the following:  4 bottles of Parker Quink (Blue, Dark Blue, Black, Green), Sheaffer Skrip (Peacock Blue), 2 bottles of Montblanc (Blue, Red), Aurora (Blue), Chesterfield (Night Sapphire), 2 bottles of J Herbin (Grey, Green), Bexley (Mountain Violet), Private Reserve Ink (Daphnie Blue), Iroshizuki – Pilot (Brown), Pelikan (Blue) and Paradise Pen (Purple).  Add to that a bottle of Waterman Blue and a bottle of Cross Black which were used up a few years back.  So what does this all mean?  At various points in time I saw a bottle of ink that I might like to try and bought a bottle.  What do I use on a regular basis?  The Parker Blue is my go to ink when I fill a vintage fountain pen.  I have not made a scientific evaluation of these bottles of ink that sit on my shelf.  I simply like the Parker Blue when I put pen to paper.  Add to that the fact that it doesn’t seem to clog pens that I put aside for a short period of time.  And, it flushes easily and thoroughly from my pens.  I am in no way affiliated with Parker nor do I write this as an endorsement.  I simply like the ink and my vintage fountain pens write well when filled with it.  What ink(s) do you use in your vintage fountain pens?  Why do you make those choices?  I would very interested in knowing.  I encourage all who read this blog to chime in.
Happy collecting!