Here are some pages from various Universal Exhibitor Books. Several of these have been published, in Graven Images for instance. Some are early announcements, made before final casting and some were never made.
Cagliostro (c. 1932) was to be a vehicle for Karloff. The property eventually morphed into
The Mummy.
Old Dark House (1932)
Early announcement of
The Invisible Man (1933) that was to star Karloff.
Dracula's Daughter (1936) was originally going to co-star Lugosi.
The Invisible Ray (1936)
The Invisible Woman (1940)
The Monster of Zombor (c. 1940-1) was a would be follow-up to The Black Cat (1940).