If were still talking about filtering which is simply EQ basically thats one thing, applying reverb, modulation effects, etc. are really considered FX Processing or just Processing.
Just about any DAW or beatmaking software offers basic LP, BP, HP filters along with Parametric EQs.....I would start there if you really just want to filter particular frequencies from your sample.
If your looking to effect the audio in a creative way that has nothing to do with filtering then Modulation Effects, Ring Shifters, etc are cool to mess with.