The series itself dates to the 1870's and was conceived as part of the Argenta line. Consequently the plates are most frequently found with an ivory or turquoise ground, and less frequently with a cobalt ground.
Each plate features one large fruit surrounded by smaller fruits, nuts and foliage.
Here's what we've found so far in addition to the melon: a pomegranate: an apple; chestnut; coconut; fig; lemon; peach; pear; pineapple; a whole orange; and a peeled orange. Why there are two oranges we can't say (maybe one is supposed to be a clementine or a tangerine, who knows) but there seems to be a consensus among collectors we've spoken to that the peeled orange is the most desired and most beautiful in the series.
There were also other Wedgwood designs that utilized the same basket weave ground such as the Wedgwood cornbread platter but as far as I can tell they're not actually part of the series but more like go-alongs.
Prices for the companion pieces depend on color, rarity and condition.
One note to all this: the Etruscan apple and strawberry plate is a copy of the Wedgwood peach plate, minus the peach! The elements are somewhat reorganized but there's no question of the relation between the two.
It was only one of many Etruscan designs with components "borrowed" from Wedgwood.