After this, he seems to have vanished from view; I don't know of any later projects that he worked on, and very little has been written about his animation.
A Passing Phase from 1966 is one of Phillips' earlier shorts. It suffers in comparison with Bruno Bozzetto's 1990 Grasshoppers, which is a wittier and punchier short with the same basic idea, although it could be argued that Phillips' film is more visually inventive.
1969's A Note from Above is a more minimalist film.
The Battle, from 1970. John Daborn provided the backgrounds.
I'm not sure when this one was made; the BFI database lists a 1974 film called The Losers [sic] Club and a short from 1982 called Welcome to the Loser's Club. The second sounds like some kind of remake, and because of its ambiguous title sequence this one could be either of them.
The minute-long Weird from 1973 consists of two strange characters meeting each other, falling about laughing and then walking their separate ways. Very short films such as this may account for Phillips' lengthy filmography.