ZTTO hydraulic brake calipers. They look similar to the IIIPro/ZRace XG calipers, but with just minor differences. These seem well priced, but appear to come with alloy pistons.
I detailed on this site how to convert the ZRace calipers to ceramic pistons which vastly improve performance for cheap:
https://chinertown.com/index.php/topic,6262.0.html
I'd presume the same can be done to these calipers. These initially were selling for under $30 USD for the pair. Though price has been been fluctuating.
I received my ZTTO hydraulic brake calipers last week. I haven't installed them yet, but I suspect they're a knock-off of the ZRace/IIIPRo XG calipers which are a knock-off of the Hope brake calipers!

Design-wise, they're slightly different from the XG calipers with a flatter exterior profile so they're not 1:1 copies. Annoyingly they came with the barbs pre-installed in the lines, so I either have to pull them off or install new ones (to size the cable hose to a frame).
They did come with alloy pistons. The good thing is that I can swap them out for Heppe ceramic pistons which will vastly improve performance of these brakes making them an excellent weight weenie budget buy.
On a side note, I miss the more budget aspect of this site. I like the idea of building performance bikes under a certain price-point. Even the Chinese bike scene can't escape its own form of gear elitism!
