D.R.O.I.D. is a supplement for FIST that functions a bit like the Automatron dlc for Fallout 4. Heaps of new robots are added to the game. Rules for making your own robots are added to the game. And it's all done with a surprisingly small amount of text.
The PDF is 5 pages, with a decompressed, zine-y feel to its layout. The font sizes are large and everything is spread out, making it a really easy, really quick read.
The writing style is informal and friendly, and the mechanics are easy to follow. Bots are built from three randomizeable parts: chassises, weapons, and quirks. Generally speaking, most parts have upsides and downsides, but weapons are more of a linear scale. This means that if you roll a strong weapon, you probably have a strong bot.
Overall, this is a really neat concept, and it's executed excellently. It pairs easily with any other FIST expansions, and sets a strong foundation for the GM to build on. Absolutely a standout, even among all the fantastic 3rd party FIST material.