Schiefspieglers are high F ratio tilted Cassegrain telescopes. The High F ratio is needed to control both coma and astigmatism. The most famous one is the Kutter 4.25 inch F/26.
4.25 Schief Telescope (1) 48×36 (B&W)
Larger aperture requires a higher F ratio still like this 6 inch F/32:
6 inch F32 DelmarvaSchiefbyDGroski.len
Higher F ratios means a very small field of view so a better way to make a faster Schief is to make the secondary toroidal like this one:
But a toroid surface is not very easy to make so another option is to add lenses. Buchroeder used one correcting lens but Dittie found that two lenses worked better:
Another way to deal with astigmatism is to add a weakly curved tertiary mirror called a Trischief. Both Kutter and Buchroeder did this. Here is one:
Schiefs are never as fast as a Chief and usually have a strongly tilted image compared to Yolos or Chiefs.