Well you've got the status moves like poison and burns. Confusion can also cause indirect damage, when it occurs.
Then hazards such as Spikes, and Stealth Rocks.
Then moves like Leech Seed which will drain the opponent of their HP and restore yours.
Future Sight, and Doom Desire will both strike on the second turn after being used.
Wrap, Whirlpool, Bind, Clamp, Fire Spin, Magma Storm, and Inferno can all cause indirect damage. These moves cause direct damage and then for the remaining turns.
Then there are the two weather effects which will cause indirect damage. Sandstorm will damage Pokemon that are not steel, rock or ground. Hail will damage Pokemon that are not ice type Pokemon.
I'll look for more, but I think that's all.