Philosophies generally don't have Hegelian antitheses -- they are too diverse and particualr.
But the closest to the existentialist focus on a) experienced life, b) human agency, and c) an open future, would be:
a-prime) Behaviorism ignores experience, in favor of purely external 3rd person reality. Eliminative materialism says that consciousness is irrelevant, as it reduces to neuronal behavior. Delusionism holds that we are not conscious but are deluded into thinking we are.
b-prime) Non-agency. Both the delusionists, and the eliminativnests basically leave no possible role for agency, so they both hold by b-prime. Behaviorists can effectively believe in agency -- B F Skinner famously set up reward-punishment routines for himself to motivate/train himself to be more productive. But b-prime can be held by all sorts of other people too. All models of psychology that hold that we are solely subject to psychological compulsions fall under b-prime. For instance, a contemporary dualist advocate of libertarian free will, Richard Swinburne, considers psychology SO compulsive, that we can only exercise free will when psychological pressures are almost perfectly balanced.
c-prime) Determinism. Any "compatibilist" holds by determinism, and between hard determinism and compatibilism, that is something like 75% of philosophers, so lots of c-primes. Determinism is an outcome of either a clockwork universe worldview, OR of a block time view
Block time is what one gets from Einsten's time space continuum, OR from putting a transcendent God outside time. Our future is knowable in either case.
Who believes in A-prime, B-prime and C-prime? Daniel Dennett is a delusionist, so has A and B prime, and a compatibilist, so has c-prime. There are no doubt other philosophers as well, as the primes are pretty widely held views.