Good altcoin for FPGA effort?

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I have access to several modern Xilinx FPGA boards.  They are no longer useful for their original purpose, but have PCIE, ethernet, USB and their own dedicated DRAMS and ARM processors.

I'm thinking about trying to develop a miner with one as a project to learn more logic design.  What is a good altcoin algorithm for FPGA that is not already overwhelmed by ASICs?  This would just be to see if I can figure out enough logic design to make it do something useful.