I'm a bit surprised by such a list, since, as I see the term, being antispeciesist means nothing more specific than just opposing speciesism - defined as taking species differences as ethically significant per se. That definition is not linked to any particular philosophy, except that it defines speciesism in terms of ethics. (A Marxist, for instance, might take other approaches.)
In other words, most organisations that are for animal rights are antispeciesist; it's just that for some reason the term is not much in use in English-speaking countries. The list should thus be much much longer!
Other approaches than the rights approach - such as Peter Singer's utilitarian approach - are antispeciesist too.
In France, the term is more frequent than that of animal rights. That may be because it was first introduced here by the antispeciesist journal
Les Cahiers antispécistes - by others and myself, with mainly an anarchistic, utilitarian and anti-naturalistic approach, but publishing articles from many other points of view, such as Tom Regan's, Steve Sapontzis's, etc.
The first link mentioned by pelagus is, at least as far as I know, not specifically associated with the Gary Francione approach; it is somewhat like the
Cahiers antispécistes, but more anarchistic.
David