Any Ethereum cold wallet for Linux? How to create transactions to send ETH offline and send them later?

I want to store my private key offline, I don't want to trust my key to smartphone (which I've saw most wallets run on). I have spare old PCs and I like open source. So I envision I create transaction(s) to send ETH on offline PC, copy them to connected one (or smartphone) and send it. I could not easily find software to do that. I've searched for "ethereum cold wallet for linux". Is there any? TIA