Cornflake Crumb Substitution

breadcrumbs (dry and fine)
or
panko
or
cornmeal
or 
cracker meal
or
melba toast (crushed and tossed with oil)
or
other plain breakfast cereal flakes (crushed)
or 
corn chips (crushed)
or
potato chips (crushed)
or
coating mix
or
pretzels (crushed) can be substituted for cornflake crumbs.

Cornbread Crumb Substitution

breadcrumbs can be substituted for cornbread crumbs.

Chocolate Wafer Crumb Substitution

Oreo cookie (Crush filling and all, in a food processor fitted with a metal blade.)
or
chocolate graham cracker crumbs
or
graham cracker crumbs
or
vanilla wafer crumbs
or
Salerno butter cookie crumbs

Vanilla Wafer Crumb Substitution

graham cracker crumbs
or 
chocolate wafer crumbs
or 
Oreo cookie (Crush filling and all  in a food processor and omit additional sugar in crust recipe.)
can be substituted for vanilla wafer crumbs.  

Graham Cracker Crumb Substitution

Vanilla wafer crumbs (These are sweeter, so add less sugar to a crust mixture.)
or
zwieback crumbs (great for cheesecakes)
can be substituted for graham cracker crumbs.  

Gingersnap Crumb Substitution

graham cracker crumbs
or
vanilla wafer crumbs
can be substituted for gingersnap crumbs.

Breadcrumb, dried Substitution

cracker crumbs
or
croutons
or
stuffing 
or
cornflakes
or
matzo meal
or
panko
can be substituted for breadcrumbs.