Polyamorous: interested in multiple, serious relationships.
Lesbian: Interested only in women
Involved/Available: Currently in a relationship, and potentially interested in more

We're not looking for someone new, but would be open if the right opportunity presented itself.

The website that used to host & sell these is long gone. These buttons were originally designed to be used at cons so that people could tell at a glance whether the person they were hitting on was open to being in a relationship. These handy icons were also provided free of charge. I'd link to the source, but datingstatusbutton.com doesn't exist anymore. oops, just I did.