They're a topic that generates a lot of impassioned discussion, mostly because every time they come up, everyone starts arguing about the affordability of Magic and how WotC makes the game too expensive to play. There is increasing acceptance of proxies in certain situations , especially provided you are not trying to use fake cards and pass them off as real or using them in tournaments where they're not allowed
In Draconic Domination, it is fantastic, since copying a giant flying monster is nearly always going to be worth the mana, especially if you then get some extra Dragon attacking triggers
I will be transparent and say that I believe if any of these are ever to return, the most likely one is Jeweled Lotus due to its one-shot nature, iconic feel, and ability to help support high-mana value commanders
Selvala, Explorer Returned Selvala, Explorer Returned has that critical combination of ramp and card draw, tempered by giving your opponents some card advantage as well