Many, probably the majority of aquarists keep invertebrates. Captive reef systems are plentiful nowadays with a high rate of success because of the information available about them, including many invertebrates that could well be considered as livestock.
Information and identification are the two words in mind here – the reef aquarist could make use of the following website just out of general interest or for a specific need.
The link provided goes direct to invertebrates under ‘common names.’ They can also be searched for under ‘proper names.’
The website is well worth exploring as there is more available than that mentioned.