Here is mine;

Dart trap (why? Because you can upgrade it with a relic that gives each dart a 15% chance to do a chain lightning. This is a synergy with a thing on the skill tree that causes lightning to stun. You can also upgrade both the damage and the rate of fire on the dart traps so much that they eventually shoot over 4 times per second, doing hundreds (and at higher levels, tens of thousands) of points of damage each. The dart trap, when upgraded, can also knock back opponents, pushing them back and possibly into water or other hazards.)

Harpoon Trap- This is a great trap, both in terms of damage and its ability to pull monsters to their doom. You can also build an ultimate harpoon trap that does chain lightning. And, like the dart trap, when upgraded, this trap does thousands of points of damage.

Chakram Trap-This one isn't useful until you have the relic that causes it to push back. Then, like the dart trap, it can be used to push monsters into hazards. The damage is low, however.

Bola Trap-With two upgrades, this trap puts a permanent 60 percent (or 70% with ultimate) slow on the opponents. It's great to put them throughout the path of the monsters here and there. Low damage so you only want maybe 5 percent of your wall traps to be bola traps.

Barricade-this isn't a trap, it's used to change the path of the monsters. A must have. It can also be used to make gold. Hide a bunch of gold making barricades somewhere and you will have a good cash flow.

Rocket Trap-This trap is expensive but it's the only floor trap that shoots with a very long range. It does a LOT of damage, which is also area damage. Especially if it's the ultimate version which fires eight rockets. This one is a real killer.

Teleporter Trap-This one is great to put next to hazards, like water and deadfalls. It causes monsters to get teleported into the hazards. The ultimate version can teleport them back to the entrance, which is great to put near the exit.

Shockwave Generator-this is a useful trap that can destroy bridges that some of the monsters build over hazards. It also can both silence and slow the monsters, when upgraded. The ultimate versions aren't very good.

Lightning trap-This is a great damage floor trap. When you have the stun skill upgraded on your skill tree, it also stuns and slows the monsters.

Some I don't use all the time but they are very useful, like the slime trap, soul harvester,
black hole traps.