Given you have free electricity, your first move is to start mining with what you have. You can use Nicehash and have it autoselect which altcoins to mine and have it automatically convert to Bitcoin, or you can "cut out the middleman" and figure it out for yourself. The latter is likely to return more profit, but obviously takes a lot more work.
They even have a calculator so you can estimate how much you'll make. It's useful even if you do not plan to use Nicehash, since it's better to err low on expected revenue.
https://www.nicehash.com/?p=calcAs for ASIC miners, just take the TH/s figure and divide by how much the miner costs. (Optionally add in the cost of PSUs and other accessories, but they can be reused so I don't consider that the same.) Do note that S5s are fairly noisy (can be modded to be quieter) and anything newer even more so. That really pushes things towards altcoin mining, even if you have free electricity.
The GPU coins I mine are Curecoin and Foldingcoin (they can be "merge mined"). While they might not give the best profit, they do have the nice side benefit of helping to find cures for cancer. Basically a way to get paid to help save lives.
HDD coins like Burstcoin, Sia (might have a GPU part to it as well, don't know much about it), and Storj along with smartphone coins like (defunct) Perk are good for energy efficiency, which is clearly not a priority in your case.
