I like the impromptu Bob Longe version.
It has been published in The best card magic by Bob Longe.

That would have to be "Day One" by Scott Cram.

The classic day for any date ... and they can check their mobile

Assuming I'm not carrying any props, mine are day for any date, psychometry with a personal object, brief palm reading, or a memory demo.

Against All Odds by Sankey.
Uses a regular deck. Simple but always gets a reaction.

The most impromptu trick I got is a finger removal trick I invented... not the old thumb one but a new one I havent seen described anywhere yet... and with just the hands involved theres not much that could be more impromptu... maybe a Baldacci levitation... but those require some working up to usually for people to truly believe....

I think the salt shaker through table trick has always been one of the best ones you can sorta do with a cup and a napkin even if there's no salt shaker around...

TTCBE by Eugene burger

Earth Shoes by Looy Simonoff
With thoughts from Gerald Deutsche.