Some of the best Orzhov cards are not technically gold cards but do need to be played with access to both colours of mana to be worth it, as such the top ten is a top thirteen just in case you don't think they should count
Wurmcoil Engine The best thing about Wurmcoil Engine is that it cuts down on the negative side of spending a lot of mana on a big creature
If you print proxies often, this is the difference between ill actually use this and ill do it later (you will not do it later)
Mono-White Hammer runs Lurrus as a companion, which happens to be one of the best decks in Modern at present
Some cards go up in price later, but even so, no one likes getting ripped off
3 Liberator, Urza's Battlethopter Speaking of incentives for playing additional artifacts, Urza's Battlethopter is perhaps the best artifact incentive currently available in Standard