Maybe you know about this, But if not I hope it can be helpful. Sorry if this is a known thing or something.
I was going to look at just blue instants. Using the word "instant" in the field "type". Then every other, card type "land, creatures, etc", came up but "instant"
so I typed counterspell into the card search just to see, Counterspell appears in the list but its from an older set with the card type "interrupt". Also if a instant didn't have a old "type" "interrupt", "mana source, etc" so the card does not even show up.
so I tried "cannot be the target if spells or effects" this gets rid of 1996 world Champion. i would assume other cards that also have that wording.
i'll let ya know if i find anything else that could be useful for development.
useing playtable 0.31 - windows 7