I cannot store many altcoins with trezor or ledger nano s.what is the solution to store coins for long term that are not supported to trezor or ledger?
Coinomi is one of the best multi Support coins wallet which support many reputed cryotocurrency but can say what the altcoins to store then the people can suggest you the best wallet.
MEW is another option if your coins is based on ERC20 but you can't store litecoins or BCH in MEW,so you need to select the right wallet for your coin.