If you talking about successfull in terms of technology then I am pretty many of the top coins can e justified as successful ICO's

But in terms of profit I recently invested in Electroneum Coin due to lot of shilling coin on the internet. Had invested $200 and each coin was around $0.01 plus some early bird bonus gave me 21000 coins. When it hit the exchange the price was $0.08 and I got too excited and dumped everything with a easy profit of $1480 doing nothing. Now after a month the price is $0.16. I do feel regretted of dumping all the coins tough.

Anyways ICO's are great way to make easy quick money but also a bit on the risky side.