His findings: Adding extra cards is not a good way to tweak mana ratios: the added variance of the 61st card tended to be greater than the value of getting your lands-to-spells number just so
These platforms can give you a good idea of the current market value for individual cards
Grenzo (Conspiracy 2, 2016) was another early attempt at this, but it isnt played much even in EDH, where EDHREC only lists 417 decks with it
You can certainly make this work, but I don't know exactly if this is a wave maker
On the other hand, Discreet Retreat is another very powerful, but very narrow card: For 4 mana, you get ramp, color-fixing, and card draw on a land enchantment - but once again only if you're dealing with outlaws
You can really get into the abilities of your cards here to represent characters from your favourite stories and it can actually end up being fairly powerful if you choose wisely