Metal J moulding comes to mind but I really don't think it would look right there.
Really, the best option is exactly what you have, just a roll and tuck with clean, straight lines.
BUT
In older homes, there will usually be a hardwood moulding around the tile. Shaped in a sort of a T, the moulding laps over the tile on one side and over the carpet on the other. The carpet must be cut back or tucked under enough to get the moulding (bottom of the T) fastened directly to the floor.
I suppose it could be painted or finished in a lot of different ways.