I have a computer constantly connected to the network with free electricity. Of course, I could mine, but I have outdated hardware + I don't like the idea of meaningless calculations.
I want, without investing my own funds, to support the ecosystem of any coin and receive currency for it. For example, my computer can contain the entire blockchain, verifying the history and current operations, saving the network from an attack of 51%.
Please, tell me about similar coins.
Not doing "anything" is always impossible, there is nothing that gives you free coins. If you are looking to get free money from airdrops you need to get that yourself, which is not "free" but quite close, if you want bounty that means you are looking to work for the coins instead of buy those coins, which means you value your time less then you value your money which is alright for some people specially in third world countries but not for everyone.
If you are looking for staking that requires money which is not nothing, you basically invest your money into that coin and hope you will make a return from it. Basically no matter what you do there is no "free" money, you always either spend your money, your time or your effort for some returns and they all cost, maybe not money but they all cost something.