Note that RGB / base / tone curves are all limited to values 0…1, and can therefore result in hard clipping.
I mostly use filmic’s contrast for quick adjustments – but, as others said, there the contrast is fixed at mid-grey (which is often fine, as I want to adjust the mid tones, not the extreme shadows or highlights).
color balance rgb lets you move the point (the fulcrum) around which contrast is increased (brighter pixels become even brighter, darker ones become even darker).
tone equalizer has presets:
The simplest way to adjust the fulcrum is using the mask exposure compensation control on the masking tab – but this may be a bit confusing, as a higher exposure compensation brightens the mask, shifting the mid point, which is the fulcrum, towards darker pixels:
For example, with the mask exposure compensation shown above (note: the mask is enabled):
With a higher value - the mask shifted, and looks different:
The original image (from [PlayRaw] Sunset on ferry):
Contrast with the original exposure compensation:
Contrast with increased exposure compensation (fulcrum effectively shifted towards the darker pixels – note that the mouse hovers over a pixel where the mask has a value of about -4 EV – that’s the fulcrum now; pixels darker than that become even darker; brighter ones even brighter):
Finally, with a large negative exposure comensation, the fulcrum shifts toward very bright pixels, meaning that almost the whole image is darkened:
You can combine the contrast effects (both for color balance rgb as well as for tone equalizer with parametric and/or drawn masks) for finer control.