I mean, I really love this card and idea. But it's rife for abuse. Round 3, play Mistwalker. Round 4, Perfect Shot Mistwalker to scry 261 yourself. ;p

Oh, wait, did you mean types? I presumed creature types, but that's not what you wrote. So you get scry 2 if it's an artifact creature? Far more realistic. Might require reminder text.

No, it's supposed to creature types. That was an oversight on my part. With changeling not being in the set, I'm skeptical if those abuses would be relevant in a competitive sixty card format. A player can scry through their whole deck for five mana over two turns. That sounds good, no doubt, but I'm pretty sure more obnoxious, broken things in real Magic exist than this.

Well, certainly there are. Turn one wins.

The downside of this one is its potential repetitiveness. Every time you pull it off for a decent number, you can rig your deck to arrange your combo to go off. Which isn't quite enough for an opponent to just shrug and move on to the next game; but is going to make all your games kinda samey and boring. ("Well don't do that, then" is good advice, but seemingly impossible for some sections of the population.)

As a side note, there are abilities that don't go out of control (usually) when you scale them. Give a creature +0/+X, for example, is meaningful when it's the difference between +2 or +3, but doesn't wig out at +261 without shenanigans. Likewise with exiling cards from a single player's graveyard, or put a +1/+1 counter on up to X target creatures. There's more.

I think you're right that in the grand scheme of things, this might not see play in tier-one 60-card land. Maybe not until people are already main decking against lots of legitimate flying threats. (Combo-control decks are admittedly funny and might play this combo out on turn 12 to win the game. But it's a maybe.) I'm also pretty sure it would be banned anyways, for the same reason that Shahrazad andSensei's Divining Top is banned. It's rife for abuse when intentionally stalling in a tournament. But that's only important if that bothers you. Like I said, I like the card. And if it works within the internal logic of your set, then I don't see a problem with it.

The mere fact that it's even possible to scry your entire deck means this shouldn't be printed, imo. Caring about number of creature types should only be used for bounded results

Non-Shapeshifter. Very clever. ;)

I suppose if you wanted, you could make it even more obsequious by saying something like 'non-Juggernaut' or 'non-Wall', or whatever other creature suits your fancy. It's going to catch changelings all the same.