**broken link removed**
Think that's it. Tetramethylammonium hydroxide solution.
But I don't think that' necessary. I used to mix my own developer, NaOH I think. "Red Devil Lye" is pure NaOH. But be aware it's dangerous in concentrated powder form. Strong bases are as dangerous or worse than strong acids.
Important hint- if you spill the powder on you or something else, brush it off, sweep it up, but never try to wash it off or mop it up. The powder won't affect anything until it gets wet.