Suitable varieties come from the 'neutral' group: fresh, neutral wines with fine delicate bouquet. Other varieties, with stronger flavours and aromas, do not produce good Sparkling wine. As well as suitable flavour a variety must retain a high acidity.
Reichensteiner: has been used in England with some success, it has good ripeness and acidity but has a very slight 'muscat' flavour which means it is not ideal.
Mid-season to late harvest:-
Auxerrois: loses acidity quickly as it ripens so is not ideal.
Freisamer: a Pinot gris crossing. Trials in Germany, on the upper Mosel, have produced a methode champenoise which is indistinguishable from fine Champagne. I have used some Freisamer grapes in my own Exmoor Brut, blended with Pinot noir.
Orion: I've not heard of this being used for Sparkling wine but I can imagine it would be interesting.
Pinot blanc: has a much thinner taste than the other Pinots, and ripens slightly later, so there is no point in growing it.
Pinot gris: more than a century ago it was grown in Champagne, but faded out because of the relatively low yield. With modern clones/selections giving higher yields it is the equal of Pinot noir. My first experimental Sparkling wine was from a small quantity of our 1987 vintage Pinot gris, I took the base wine to a top producer on the Ober-Mosel who made it into one of the finest 'champagnes' I've ever tasted.
Pinot meunier: the third Champagne variety, grown for quantity. The stronger flavour is too coarse to produce really fine Sparkling wine.
Pinot noir: the most delicious Champagnes are made from Pinot noir,
those from the Bouzy Grand Cru in particular; 'blanc de noirs' or 'oeil de Perdrix' (partridge eye).
Seyval blanc: used in England with great success; however, these wines generally have relatively low acidity and are not like Champagne in character.
particular about the soil it is grown in, chalk/limestone is really necessary to
produce the correct flavour; in red sandstone or clay it does not taste good.
Elbling: used on the Ober-Mosel and can produce a nice Sekt but the flavour is really too unripe.
Riesling: widely used on the Mosel and in Luxembourg but really has too much flavour.