Whirlwind
The Whirlwind Artillery Tank is the standard artillery piece (in fact, often the only artillery piece) used by Space Marines.
It starts life as a Rhino chassis, like most Space Marine vehicles, but differs in that its carrying capacity is sacrificed to hold ammunition for the Whirlwind Multiple Missile Launcher on top.
Helios
The default Helios-pattern launcher fires anti-infantry missiles, giving the Space Marines anti-horde support. They don't use this tank in the way that most Imperial Guard armies use their artillery; while IG artillery supplies sustained bombardment of static positions (enemy forts, armies, cities, etc.), the Whirlwind fires a quick barrage of devastating firepower to support Space Marines who need it, and then moves on to the next trouble spot.
The Land Raider Helios takes its name from having this type of launcher.
Hyperios
Produced by Forge World, the Hyperios-pattern launcher uses a different targeting system and fires anti-air rockets (after attempts to use anti-air rockets in the Helios launcher proved "disastrous").
In the first installment of the Horus Heresy books by Forgeworld, this has both skyfire and interceptor, meaning it can serve as a decent light-AT weapon in a pinch.
Scorpius
The Scorpius pattern is also made by Forge World, for the Horus Heresy line. It stores S8 AP3 Blast missiles in rapid-firing rotary drums, and can fire 1+1d3 at a time if it sits still. The design was commissioned by the Space Wolves to help them take xenos cities, and was intended to fight on the front lines, so it has armor plating like the Predator Tank, which makes it beefier than the other patterns.