I think most intellectual property is arguably good, in the sense that you could make a good argument for them being useful and I wouldn’t dismiss them out of hand.
The one kind that I think is definitely good and useful is trade marks, because brand recognition has huge economic efficiency boosts.
However, if you’re asking “Which type of intellectual property should the law definitely protect?”, this is probably the weakest area, because the law is already 100% unnecessary for it, because cryptography.
We can sign things with public keys now to prove beyond a doubt that they came from the right person. Verifying such signatures is now cheap. All you need now is to start cryptographically signing labels by having tiny QR codes you scan with your cellphone. And then, boom: No more counterfeiting at the consumer-level.
(Mimics of status goods will still exist, though, because it’ll be rude to scan your guest’s dress at a party to make sure it really cost them $2000. But, like, fuck status goods.)
Many if not most people would just pirate movies in that case, removing the money required to make the big ones or switching us back to a patronage system.
…Many if not most people would just pirate movies if studios didn’t have legally enforced brand names?
…You know that trademarks and copyrights are different things, right?
Sorry, I misinterpreted your post as being broader than it was intended during the latter part. In my defense, I’m running up a sleep debt.