Sandking

The Sandking is a two door, four-wheel drive racing SUV. It's cool. It does have oddly dark textures.

It is located under the Big Ear, the huge satellite dish.

 

More info:

gta.wikia.com/wiki/Sandking 

https://www.grandtheftwiki.com/Sandking 

Monster

The Monster are a family of monster trucks: huge two door, four wheel drive monstrosities. I tend to think of them as pick-ups rather than SUVs. Instead of a handbrake they have 4-wheel steering for a tighter turning radius.

As fun as it is to run over other cars in them, this tends to catapult them up in the air leading to roll-overs.

There are three main types:
1) A plain version found just across the bridge from west Los Santos.
2) A red, white, and blue version with a spoiler owned by Michelle Cannes in San Fierro. You need to date her to 50% or use a tow truck. There are 2 variants of this: with or without lights.
3) A red, white, blue with yellow/black checkers version. This is found near the stadium in Los Santos after beating the hotring challenge. There are 4 variants of this one: lights on a roll bar, lights on the roof, spoiler, or nada.

For those of you counting at home, there are 7 total variations:

 

More info:
gta.wikia.com/wiki/Monster_Truck
  http://www.grandtheftwiki.com/Monster_Truck

Dune

The Dune is a large four-wheel drive truck designed for off-road racing. It can tip over a little too easily though.

The Dune spawns near the stadium in Las Venturas after completing the Kickstart challenge.

More info:
gta.wikia.com/wiki/Dune
https://www.grandtheftwiki.com/Dune

Bloodring Banger

The Bloodring Banger is a modified Glendale used for destruction derbies. Its doors have been welded shut so CJ enters through the window.

You need to win the Bloodring challenge (or use the OLDSPEEDDEMON cheat) to get the Bloodring Banger.

More info:
http://gta.wikia.com/wiki/Bloodring_Banger
https://www.grandtheftwiki.com/Bloodring_Banger