While I do not collect posset pots (because of their price) they certainly fall under the umbrella of "ceramic feeders" and need to be mentioned.
Posset pots are spouted two handled vessels from the 17th and 18th Century used to consume "posset', a beverage containing a cocktail mixture of curdled hot milk or beaten eggs, often including wine or ale, often spiced or sweetened, and often thickened with oatmeal or bread. They have lids to keep the contents warm with the floating custard portion eaten from the top with a spoon and the liquid lower portion sucked from the spout. They were most commonly made in slipware and delftware and a rare few in silver. Over time the shape of posset pots evolved from simple basic forms to more curvilinear vessels with elaborate ornamentation (too nice to use in my opinion). Needless to say it does not take much imagination to understand why most did not survive undamaged (i.e., wine and ale and ceramics are never a great combination).
One area of collecting outside the umbrella of "ceramic feeders" that I developed an interest in towards the end of collecting was ladies spittoons.
I admittedly acquired one when I first started collecting because of its similarities with feeding cups (small, having a handle and having a spout) and for the longest time paid little to no attention to it (always kept on the lowest and darkest shelf of the display case). It was not until much later when deciding whether or not to keep it that I decided to take a chance and acquire a second to display along side it. Since that time I was hooked.
Another "related" area of collecting that I developed an interest in towards the end of my collecting was inhalers.
While admittedly the vast majority of ceramic inhalers are generic, plain, uninspiring and large there are some that are smaller and beautifully decorated and transfer-printed.
Similar to food warmers the search is what I enjoyed most - looking for complete sets with all their key components (i.e., bottle, top, cork and glass straw(s)).
While admittedly I have no real sense about how they work (which is laziness given many have the directions written on the bottles) they display wonderfully along side everything else I collected.
The American Collectors of Infant Feeders is a relatively small organization that holds an annual convention each year hosted by one or more of its members and publishes and distributes to its active membership quarterly newsletters entitled "Keeping Abreast".
The main purposes of the organization is the sharing of information and promotion the collecting infant feeders and related items. For those with interested please note that "infant feeders and related items" covers a significant amount of territory beyond ceramic feeders.