At the end of the 21st century, a comet struck Earth and devastated life as we know it. Some managed to escape on a spacecraft, and others managed to survive the blast which sent the planet into another ice age. Three hundred years later, those from outer space descended back to the planet - but what they found was not the world they knew before. Fierce creatures that can eat DNA now roam the land, and only the special task force of the Juno family known as the Geisters can put a stop to them. While the Geisters try their best to defeat these unstoppable foes, political turmoil and tensions run high. Those from the heavens try to control those on the surface, and believe that their Earth-bound counterparts are savages and must be stopped from rebelling. Who will survive these dark times?
In the early 21st century, the emergence of an incurable condition known as B-cell growth led some of the affected to become "Sleepers" - people put under stasis until a cure could be found. Yuji Kaido is one such Sleeper who awakens, several decades later, to a horrifying new reality. Giant bugs known as Blue have invaded the Earth, eating everything - and everyone - in sight. Now, all Yuji can do is escape from the city with the ones who saved him from his inevitable death, and make their way towards Second Earth: mankind's new home in space.
Blue Gender, like Geisters, shows us two very different groups of humans who survived an apocalyptic event in very different ways. Luckily, unlike Geisters, Blue Gender doesn't suck complete ass. The monsters are badass, the characters are better, and overall you should enjoy it.
One day, the brave hunter Kyle and his lady Alita are out hunting creatures when suddenly, a large black dragon appears, kidnapping Alita and killing their companion in the process. Hope lies only with a powerful blue dragon named Blau who is hell-bent on putting a stop to the black dragon's sinister plans. Now, in order to save Alita and prevent further destruction, Kyle must join forces with Blau and stop their opponent from reaching the black tower before it's too late!
Panzer Dragoon and Geisters are both outlandishly bad anime, from the freaking horrible CG to the poor excuse for a story. If you for some reason liked one, I'd imagine you'd be the kind of person to enjoy the other two.
It is the year 2023, 30 years since the time of the Silent Crisis that brought the world to the brink of destruction. In the present, other-dimensional beings known as the Lucifer Hawk are running rampant, and threaten to take over the human world. The only hope for mankind is the AMP -- the Attacked Mystification Police -- a group of women with paranormal abilities who are dedicated to stopping the Hawk at all costs. With the frequency of attacks increasing and the bodies piling up, it's up to Katsumi Liqeuer and the rest of the gang to stop the invading threat... before it's too late.
Basically everything about Geisters is hands down godawful. If you'd like something better, definitely check out Silent Mobius. It has an extremely similar feel, follows another group of badasses who hunt monsters, and in general is better in every single way. I can't see why you'd like Geisters and not Silent Mobius.