A uniform field of 50kA/m causes about 63mT (Vs/m2) in air. Depending on the shape of the ferrite (for example le/D ratio ) and the orientation to the field, the flux density inside the material may increase significantly (factor 10 is not uncommon).
The AM ferrite antenna oriented parallel to the field is an example of where the flux in the core material is far higher then the undistorted flux density. Such a ferrite stick will definitely show saturation.
Even a sphere will "attract" field lines, so your 50kA/m field will bias your ferrite material certainly above 100mT. When you use "open" coils (bobbin style inductors), inductance variation because of the DC field will not be that high as most wanted field already goes through the air.
You may notice more distortion in your analog circuit because of asymmetric behavior of DC biased core material. You can compensate for that by using two coils in series or parallel with opposite polarity
If it's just LF filtering, would switched capacitor filters do the trick? Magnetic flux at low frequency is hard to shield, and sensitivity to ambient field isn't usually spelled out in the inductor data sheet.
If it's bucking converters that are an issue, simply using overrated units will probably work. Power component saturation isn't likely to do anything but tickle the overcurrent shutdown in any case. Filters that change character according to uncontrolled B-field, though, are a nuisance. I remember a friend trying to match capacitors who said the bridge was giving him different values every time... and the problem turned out to be BX type ceramic capacitors being altered by his body heat as he held them to attach the bridge probes.
Nonlinear inductors aren't any more tractable than those nonlinear capacitors were...