If you are looking for online wallets for altcoins ERC20 then MEW & MetaMask would be the best choice, if you are looking mobile wallet for ETH & ERC20 tokens then you can use MEWConnect wallet for IOS only, for storing multi coins you can use Infinito mobile wallet. If you are going to store a large amount of LTC or other tokens/coins then buy a hardware wallet Nano LedgerS or Trezor.