Many possibilities. You'll have to narrow some of them down by whether you're getting spark, or not. If there's no spark, it could be the crank position sensor, 1 or more ignition coils or the ignition control module. If it's getting spark, then it has to be a fueling problem. Could be 1 or more injectors, or the fuel pressure regulator leaking. BTW, how did you test the fuel filter? It's only around $10 for a replacement one, and technically, they should be replaced once a year, so you may as well do that. How did you test the fuel pump?
Also, what is it doing when you try to start it? Just cranking, but won't turn over? Is it struggling to crank at all? If you have the vaults gauge on the car, is it showing adequate amps to start the car (around 11)?
