I think Ulamog, the Ceaseless Hunger will be the big payoff and will be the go-to Eldrazi of choice
The other three legends dont look amazing, all things considered
If you are selling played cards, I think the scale tips slightly in favor of eBay (make sure to take pictures and list clearly), followed by TCG, with buylisting bringing up the rear simply because most buylist make heavy deductions for played cards (ranging from $0.70 to $0.30 cents on the dollar)
Disney Lorcana hits that sweet spot of offering a cavalcade of classic characters to collect, as well as being a fun and surprisingly deep TCG, and thanks to Amazons Spring Sale, you can save a fair amount of money on some of its sets, too
Donald Duck, Becaneer seems to do everything this Hero-centric challenger deck wants to do
Card draw is one of the essential pillars of any Commander deck