Dead:
All 4 of my grandparents. I was the baby of the family and missed out on all of them in their younger days. Didn't get to meet my maternal grandfather as he died 2 years before my birth. After that, it's kinda hard, but I would say Mickey Mantle.
Alive:
This seems crazy, but I would give anything to have a meaningful conversation with my dad again. His dementia came on suddenly after a heart attack 2 and a half years ago...one day he was his usual self, the next, he's hallucinating and talking nonsense....and he's pretty much just a shell now. I used to hate when he would tear into me about things, but damn....I miss all of that so much now.
Jerry Miculek (professional shooter and record holder of many shooting titles)
Bill Murray (saw that above, that's a good one for sure)
Harrison Ford (although, I would imagine there would be a lot of pregnant pauses with that conversation lol)
Clint Eastwood