regalman
Reckless Dolphin
I'd limit it somehow but keep it somewhat similar. Like...
"Luxury resources on freshwater tiles yield +2 production."
"Upon claiming a freshwater tile, receive a boost to production in that city."
"Improvements on freshwater tiles yield production equal to their base yield"
"Upon constructing an improvement on a freshwater tile, receive a boost to production in the nearest city."
"Freshwater tiles yield production when constructing faith or culture producing buildings"
Ideas in bold work best with the other uniques. Though they all synergise pretty well I think.
fantastic ideas! Hard to decide which one to pick but I'm leaning towards the last or the first one.