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I started with some tables from http://www.apolitical.info/webgame/tables.php?mode=4&backto= but added lots of options and complications, as well as noting the trigger of each trap. Descriptions are systemless, apply appropriate rules for whatever game you are playing.
A beam of arcane energy targets one character per round. Anyone struck by the beam (who fails to dodge) is teleported to the rooms of the main villain of the dungeon, where they will find themselves in chains. The trap is triggered only by magical light.
A pit opens up. The 'pit' is actually the mouth of a hungry creature. The trap will only activate if a person taller than 5' walks beyond a certain point.
The walls grow warm and then begin to glow red and then white hot. Within 7 rounds anyone in direct contact with walls, floor, or ceiling of the room will suffer severe burns. Those insulated (e.g. by standing on furniture) may be protected. Any noise louder than a whisper will set off the trap.
One person falls 90 feet, taking damage as appropriate, due to a magically disappearing section of floor. A tripwire will activate the trap.
A pit opens up. The pit is empty. However the inhabitants of the dungeon check it regularly, and are likely to kill anyone they find. Magical glyphs will activate the trap if any living being comes within 10' of them.