The smallest FPGA

https://www.digikey.com/en/products/detail/microchip-technology/VERYVERILOG/29020656: $13.31 for a tiny, tiny programmable logic chip.

https://www.digikey.com/en/products/base-product/microchip-technology/150/PIC16F13145/733403: The raw chips for the above, cost a dollar or two.

DSP

Trapezoidal filters

Coincidence counting

Learning

BYU computing Boot Camp: Better than nothing, but still has holes.

The Art of FPGA Design: Specifically about delay blocks, but has other useful tidbits.

FPGA Design Elements

FPGA Design Process: Also has a bunch of other useful tutorials, but is beyond intro level.

Mandelbrot lab: Base site also has useful stuff

Quartus examples: From Cornell ECE5760

Altera Cookbook:Also from Cornell

PYNQ

Official Site: Very broken

Community projects

Github Tutorial: Also a bit broken.

PYNQ-Z2 Has info and links to resources. Somewhat broken.