There have been many different ICO's launched on the Ethereum blockchain, each with their own unique and interesting selling points. One that I feel is worth watch, is Civic. They will be releasing their token in a pre-sale on 21 June.
Civic have created a "Secure Identity Platform" (SIP), which uses a verified identity for multi-factor authentication on web and mobile apps. Basically, it alleviates that hassle of constantly having to sign-in with usernames and passwords, and also ensures more protection against password and identity theft.
Civic has many reputable partners already, and with plenty more rumored to come, I feel that this is definitely an ICO to watch. Civic tokens (CVC) will be made available tomorrow, and you can purchase them with both ETH and BTC.
For more info, visit their website: https://www.civic.com/
Or check out the ICO on TokenMarket: https://tokenmarket.net/blockchain/ethereum/assets/civic/