Artillery/ Firing Blindly
This strategy is pretty much the complement of Scouting. In the event that you can't see any enemy aliens... you could go look for them.
Or... you could just bombard the area, and kill anything that MIGHT be there.
Just aim at the ground, trees, buildings... blow them all up with impunity. Also, the clouds of smoke you kick up are a good defensive shield. If you manage to kill something, hurray! If you don't... oh well, that's what spare clips are for. Cheaper than your soldiers lives by far. If you fired off a Large Rocket or Auto-Fire AC-HE, and got multiple kills in one salvo, feel jubilant the first few times, then come to realise: this actually happens with alarming frequency.
A Heavy Rocket costs $900. A full clip of Auto Cannon Heavy Explosive rounds costs $700. A grenade costs $300. These are probably the 3 most effective weapons for area bombardment, other than Blaster Bombs, which I deem to be near priceless. A heavty Rocket also has better terrain destruction capabilities than any explosive other than the High Explosive and the Blaster Bomb.
Obviously, the Heavy Rocket is the most effective and powerful option. 100 explosive power. Scary. Trouble is, it takes up a lot of space, uses up a lot of TU, is very heavy, and is expensive. However, it blows up a pretty huge area, and does a lot of damage. Also, a Heavy Rocket will almost always One Hit Kill a Cyberdisk. Sadly, the Heavy Rocket has a high chance of blowing up a lot of loot, because those alien guns can actually withstand explosions from AC-HE, but not these things.
The AC-HE rounds are very very economical, both in TU and cost. You get 15 shots with 42 power each. Not bad at all. For comparison, the Heavy Cannon is 6 shots with 52 power.
The grenade costs $300, and has 50 power. It is quite TU consuming to prime and toss a grenade, but they have very useful arcs of fire.
Later in the game, once your soldiers become very strong, Heavy Explosives 110 power is still unutilised, since Alien Grenades have 90 power and are much lighter and half the inventory space.