Is there any way to filter out Tegra-only games?
Not with the original Android Market, as there is currently no option that would allow an developer to specify the App as Tegra (required|optional) in the app's manifest. 
Maybe some alternative markets provide this search filter. But I am not aware of one that does it.

Off-Topic: If you want to know which Apps (mostly games) are compatible with your Tegra device, check out NVIDIA Tegra Zone.