Rubber Whistle,
Go confront him, he not only steals from you, he steals from other people. It is only a matter of time before this guy get's dropped by someone for having sticky fingers.

Me personally, I would drop him as a friend. This is why I don;t lend money to friends, and I don't tolerate shenanigans in my house.

You tried to downplay what he did by stating that the Amiibos he took were not rare ones. But they were still yours. I'm not advocating violence here, you're an adult and very goal oriented. but don't keep people like this around you. When you finish your degrees and make some serious coin, what else will he take from you.

Cut ties, never good to have a thief around period.

Ok real advice time. As others have said, confront him about it. He may come clean but he may also deny it, in which case I would suggest cutting ties. Whatever he does, he has a problem and he needs to be talked to about it. Who knows if the behavior will grow to include larger forms of theft? Do you really want to be so close with someone who knowingly steals from his peers?
I've dealt with all kinds of problematic friends, from manipulators to bribers to leeches to attention seekers. The worst thing you can do is let their behavior go unnoticed. What you say in your conversation is completely up to you, but you must talk to him about it.

The first thing you should do is talk with him about it. But don't put too much pressure on him. The way it sounds, he might be suffering from cleptomania. Though I'm not a doctor, so don't consider this a diagnosis. Just make sure to tell him that you're not angry at him and itstead are trying to help. If you go too hard at him, he might feel humiliated and just get away and never come back.

Also, tell him that your friendship will suffer if he doesn't change. That way, he will at least think about whether your friendship or all that stuff is more worth it. However, cleptomania or not, people who steal have almost always a problem. Might also be too less income, but what do I know. In any case, he has to be willing to get help. You can't force him to. So be sensible, it might take some time. Just when you see that after some time he doesn't make any attempt to change his behaviour, you should quit your friendship. That's the last option I would suppose If you really like him, but sometimes, it's the right thing to do. some people just don't learn.

Go over to him and ask for your stuff again. After you get your stuff back (which I'm assuming you might, unless he's sold it or whatever), at some point in time you should steal something from him and keep it unless he asks for it again. That'll teach a lesson or two.

thanks for the kind words. honestly, one thing that i cant stand is when people hear about something someone did and have some kind of "BURN THEM AT THE STAKE!" kind of response. he could be a great friend if he just didnt do this crap.

i appreciate the responses from everyone. there were a couple of things you guys said that i am definitely going to do/keep in mind before i confront him. i have been reading your responses and appreciate your input.

Perhaps if you don't like the direct confrontation idea, maybe just casually slip in "hey, do you have any idea where my 4 amiibos went? I was looking for them all morning and I was wondering if you have an idea?" and such. And if he denies it with no guilty look, then I'm afraid you're out of sugar coating words. Maybe you can say that you won't be mad at him if he told the truth or something.

At least he didn't steal your wife... Yet...

Report those items stolen. Maybe you'll get them back, maybe not. You could tell any place that buys used games and gaming related items about him. Sounds like he's been stealing for a while and won't stop til he's caught. Only way he'll possibly change is if he's caught and punished. He may see the error in his ways or at the very least fear the consequences of his actions.

Call the cops. Petty theft is a quick way to make someone fly straight.