For me it's electrum. It is a lightweight Bitcoin wallet. It has been around for years and is under active development. All source codes are opened. Here is their official website, beware of scammer and pshing site.
https://electrum.orgElectrum is good wallet, but be sure to use newest version of it. On previous versions there was security vulnerability was found.
Hardwallets like Trezor or Ledger. If you don't have money, you can store on Electrum for some time. But in the future, I strongly recommend to spend $70-100 on a hardwallet
Agree with you. It's better to make small investment to buy hardware wallet and secure coins than loose all your btc when you catch keylogger or something similar.
are all the wallets safe ?
There are no wallets which are 100% safe. Paper and hardware wallets considered as the safest wallets. If you want at least minimal level of safety - you must control your private keys.
Aside from BTC, are all altcoins can be put there also?
