One of my favourite insert effects is The Echo effect which is included in Reason. Its color section will add some super nice sounding Limiting, Overdrive, Distortion or Tube sounds + mighty fine additional filtering. When adding it as an insert effect it needs one extra tweak because The Echo runs the signal through its Delay section which adds latency to a signal. To bypass this you only need to route the input signal to the breakout input instead of the main input and you’re set.
Here’s a demo track using The Echo as insert effect on an additional parallel channel which is mixed evenly with the original track. I am riding the parameters of the color section during the track.
P.S. Did you notice that the distortion changes the ambience of the track a bit?