Grandpa's Father's Day gift policy is usually: do not bring more clutter, do not spend money I do not have, and do not make me fake gratitude.
Set the quiz to 'Grandpa' for the relationship question. The quiz weights items toward keepsakes he will display, comforts he will use, and away from heavy experience tickets that require mobility he may not advertise.
Strongest single picks. Custom hardcover photo book of the past year, designed by you ($60 to $150). Engraved leather wallet or watch strap with a small inscription ($80 to $220). Wifi photo frame, set up before gifting, pre-loaded with 50 photos ($95 to $220).
Comfort tier. Merino wool everyday socks, six pairs ($60 to $140). Heavyweight tee three-pack in white, black, and navy ($95 to $180). Pour-over coffee starter kit ($90 to $220). Whiskey tasting flight set ($60 to $180). All four wear out, get used, and leave no clutter.
What to skip. Heavy gifts. Power tools he will not use again. Experience tickets without an offer to drive him there. Glitter 'world's best grandpa' anything (display obligation only).
If he is far away. Single-origin coffee or chocolate subscription ($28 to $80 per month) shows up on his counter without coordination. Two-week meal delivery gift card ($100 to $200) is a quiet 'you do not have to cook' he will not say thank-you for but will use every week.
The free gift that beats most paid gifts. A scheduled video call with the grandkids on Sunday morning, with each kid having one specific story prepared about the past month. The story is the gift; the call is the wrapping.