Besides fruits and milk, what other things in nature are "intended" to be eaten?
There are plenty of examples! Here is a short list


Defence ("Eat that so that you don't eat this")


Evisceration. It is the ejection of internal organs so that predator eat them but not the prey entirely. (sea cucumber does evisceration)
Lizard's tail being fragile on purpose

Parental care


Milk
Regurgitation
Sexual Cannibalism (as it is often hypothesized as benefiting the male also as he indirectly nourish his offspring)
In haplo-diplontic species, one of the two generation can be much bigger and can transfer its nutrient to the other generation (offspring), such as in moss for example.

Mutualism


Nectar
Fruits
Honeydew produced by aphids to attract ants which protect them from predators 
Ant breeding fungi

Symbiosis


Lichen
Root nodule

Social behaviour


Honeypot ant (if we are happy to consider the honey stored in the ant for a long being part of the ant biomass).

Human related


The researcher in parasitology that feed his mosquitoes with his own blood!
Crops (and other things) under artificial selection. It is here just cases of mutualism where humans is involved.