On Prohashing at least, I'd stick with Ethash as none of the other algorithms are gonna be as profitable for now. Etchash will replace Ethash in that regard within a few months with the new update though so keep an eye on that. If you wanna try out some other coins, I'd recommend seeing how your cards do on the KAWPOW algorithm to mine Ravencoin. It's not supported by Prohashing at the moment but I tried it on Flypool where I was paid in RVN and just did my exchanges on Bittrex. I don't have a good sense of profitability but comparing values given by Prohashing and Flypool, my 1050Ti was technically making a little more money per day mining RVN than ETC. To be fair, Ravencoin had just seen a big boost in price at the time so obviously individual results will vary.
Also if you have a Ryzen CPU or a late gen Intel (8th or higher), you can get a half decent amount CPU mining Monero here with XMRig. As of this post, Monero earns $0.065/Kh/day and my Ryzen 7 3700X can do 8.5Kh/s with no overclocking and running a few things in the background.
I figured out what my stuff mines best through a lot of experimentation/trial and error. Don't be afraid to try out all the different algorithms to see what kind of hashrate you get and then compare that rate to the value of that algorithm. If you care about profitability, then keep track of the power draw and factor the cost of electricity in. I noticed my 1050Ti pulls 10w more to do KAWPOW than Etchash, while the GTX970s pull 165w EACH doing literally anything. lol I mine for fun mostly so I care more about the convenience of Prohashing's features which is why I'm not trying to mine KAWPOW and instead joining everyone else passive aggressively making comments about how it needs to get added here.