This project draws rectangles using two triangles. You can see how many triangles can your computer handle per frame. For Scratch, keep the Target FPS below 29, but if you are using a.d.d.o.n.s or TurboWarp and a custom framerate, feel free to increase it, because on Scratch anything higher will result in the triangle count dropping. This project automatically adjusts triangles drawn per frame, so it is not instant, changing framerates and starting the project takes some time.
Thanks to: @Geotale @-Rex-Test- For the Triangle Renderer I got about 200 rectangles per frame on my computer (30 fps).