Could you give an example of the sound you hear that you think is compression?
As other's have said, ovnilab.com is a great resource.
I love compression. But not all compressors are created equal. After 20+ years and lots of different pedal compressors, I'm now using a rack compressor. It's great, and using a low threshold and very low ratio it subtly thickens my tone but doesn't kill my dynamics - compression as a tone tool. This then goes through to the second channel, with a high threshold and high ratio to catch any unwanted accidental spikes and makeup gain set to make the most of my amp's headroom - utility compression.
A lot of pedals give you control of only one or two parameters, the rest of the action is preset. The old Trace Elliott dual band was highly regarded by some. I had one and to me it was just an expensive, large and heavy DFA box . The BBE I found to be smaller, lighter, cheaper version of the same. I've had a few Boss CS2 and CS3s. They're the opposite. Extreme squash and pump and great as an "effect" compressor. The Maxon CP9 Pro+ was great for tone thickening. Boss LMB-3 great for "utility" compression.
One thing I've learnt over the last few years is that a lot of recording engineers won't apply just one compressor to a bass, they will apply several compressors for different qualities.