Actually, Venus Flytraps are all one species and should not be sterile, they are just not much for making seeds. They will make only a few dozen seeds at one time. Venus Flytrap differences are just genetic variations of one base type of plant, like all dogs breeds came from one genetic stock, wolves.

Most of the Sarracenias are not sterile, as a matter of fact, the "Tarnok" is one of the few I know of that is. The rest of the Sarracenias all require cross pollination to produce seeds though.

As mutant hybrid mentioned, you're really only looking at Sarracenia Tarnok. Tarnok is a floral patterning mutant that results in the pollen and ovules not developing leading to a completely sterile plant. I am unaware of any other Sarracenia species or hybrids with this mutation nor any VFT variant in cultivation that has flowers sufficiently deformed to be sterile. VFT's and Sarra's do have physical barriers to prevent self pollenation. VFT pollen and ovules mature at different times and Sarra flowers stop pollentors passing over the stigma once they have picked up the pollen. However, both VFT's and Sarra's can be self pollenated by hand. Issues of sterility are more a problem in genera like Drosera where several species have chemical barriers to self pollenation and there aren't many different clones in cultivation available to produce seed. You do also get a few completely sterile Drosera hybrids and mutants like the crestate Dosera capensis.