There are some ferns that hybridize in the garden, but not many. Any that you plant will stay true, it is just a matter of any new seedlings - the offspring of the hybridization. I don't think you'll have much of that however.

The hybridization of ferns only occurs in genetically closely related species, typically within a Genera, such as Athyrium, Asplenium, Dryopteris, etc.
For example, two separate species of Athyrium, collocated in a suitable location, may produce a hybrid offspring, such as the case of Athyrium x 'Ghost', a hybrid between Athyrium filix-femina (Lady fern) & A, niponicum, var. pictum (Japanese Painted fern).
Some ferns produce thousands of spores each year, but never any offspring (sporelings), because the conditions for fertilization don't exist in their habitat.
Unlike flowering plants, which produce seed, when pollinated, fern sexual organs must mate on or in the litter or soil near the plant. The sperm from a male sex organ (antheridia) must swim in water or a film of moisture to fertilize a nearby female sex organ (archegonia), to begin the process of offspring production.

Most fern hybrids are sterile because of the increased chromosome count and the spores never fully develop and are aborted.

Bottom line, I wouldn't be concerned about hybridization. I have grown about 100 species & cultivars of ferns for more than 20 years and have never found a hybrid! The only species I have, that produces a generous number of offspring, is the Japanese Painted fern.
Rb