I don't see any value in any of these outside of development (I wouldn't bother though) and a multiple of the revenue they generate. Even then the value will be added and not from the domains and/or potential.
Trades.pw - bad extension
Emarket.host - bad extension
fornites.us - I have no idea what 'fornites' means.
e-market.us - not sure about this one.
Remember that due to nexus agreements .us are a risk for people without an American presence to base a business/development on.
In short I see nothing here that couldn't be achieved with a reg fee alternative.