any more out there? this is getting a bit confusing!
And only two of those with original development.
Wrong ZenCash has original development built on top of ZCash the same way both ZCoin and ZCash are built upon Bitcoin
All altcoins are built upon Bitcoin! xD
ripple and monero and probably others coins doesn't share bitcoin code.
NEM , Pascal ...
They may not use the existing bitcoin core upgrades, but the early bitcoin p2p dev work is used/copied in pretty much all blockchain code...that code was pretty revolutionary.