Sponge Cake Substitution

génoise (not as airy)
or
angel food cake
or
ladyfingers
or
pound cake
can be substituted for sponge cake

Shortcake Substitution

biscuits
or
pound cake
or 
sponge cake
can be substituted for shortcake

Pound Cake Substitution

butter cake (lighter texture)
génoise (This absorbs flavors better than pound cake.)
can be substituted for pound cake.

Genoise Substitution

sponge cake
or
ladyfingers (This is also commonly used in tiramisu.)
or pound cake (not as absorbent)
can be substituted for genoise.

Ladyfinger Substitution

génoise
or
sponge cake
or 
pound cake (not as absorbent)
or 
brioche
can be substituted for ladyfingers.

Butter cake Substitution

pound cake (denser and richer)
or 
sponge cake (lower in fat)
or
angel food cake (lower in fat)
can be substituted for butter cake.

Angel Food Substitution

sponge cake
or 
génoise
or 
pound cake
can be substituted for angel food cake