No [scryfall]Elven Mystic[/scryfall] available, but that part of Standard seems to be permanently over. However, there is several fairly efficient manaproducers in the format, like [scryfall]Servant of the Conduit[/scryfall] and [scryfall]Rishkar, Peema Renegade[/scryfall] and then there’s these two:
There’s also [scryfall]Kiora, Master of the Depths[/scryfall], which might work, but I wouldn’t bet on it.