Hello, plz tell me.
Is there a web wallet? Where i can store several crypto currencies at once?
The most known are: Exodus.io, Jaxx.io, coinomi.com. Some of these wallets are not open source but they do give you control over your private keys. There is Bit.ac (I believe there is scam accusation agains them), holytransaction as web wallets but they don't give you control over your private keys, If they ever decide to scam people and walk away, there is nothing you can do to get your funds back.
Service mentioned above are the known wallets you are finding. But keep in mind that they are less secured than using a single wallet to one cryptocurrency, because they are not open source tho they give you access your private keys but we're not sure if this privaye keys are saved also to their databases which is you're not the only one holding this private keys.