There are coins with earnings without investing money?

[No Pain No blood]

I don't think there is, all investments must use money. even for bounty hunters it also costs money.
if you really don't have money to produce, it's better to be a bounty hunter. but keep in mind you must have patience and free time to complete all tasks.

[tonibyuzen]

You should first learn more information about cryptocurrency before writing such. It is impossible to get something for free. Even if you decide for the best of intentions to maintain the network of one of the coins, you need to freeze on your wallet a certain number of them. And to get these coins, you need to earn them in bounty/airdrop or buy. Moreover, I don't understand how you are going to protect a coin from attacks of 51%.

[odukoyaewatomi27]

You can upgrade you computer and start mining because it's the best way to earn without investing. In mining you are literally printing your own money. You can also consider other options like bounties or airdrop but you will have to invest your time in doing them.

[Fredomago]

With the help of your computer, especially in the current situation, you will earn almost nothing. Many have refused mining farms because they do not see any profit in it.

that's right mining isn't profitable as you will be needed to pay for electric bills with a small amount of mine coins, most of the time it won't breakeven
you will just risking your device reason why most of miners are quitting and some of them are temporary been stop while the value of each coins ain't
favorable and profitable to them.

[raven7886]

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 Of course, I could mine, but I have outdated hardware + I don't like the idea of ​​meaningless calculations.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.

[ivaf]

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.

No, man, that just won't work out. One computer and free electricity is not enough.
What you say is called a node or masternode. And to launch such a node, you first need to buy a certain amount of coins. And if you want to get a good reward, then you will have to buy more expensive coins and in large quantities.
Freebies are not here.

[Tstar]

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.

There is no free lunch. You can't expect to get something without giving something.

One of the cheapest option I can suggest you is to run Horizen Secure Node. Check here for more information https://www.horizen.global/securenodes/. While Super Node requires 500 ZEN, Secure Node require just 42 ZEN.