Monstera Deliciosa Dark Spots. You can totally move them to warmer spots if you notice your room is really cold. If it is too cold for the monstera it initially gets brownish to black spots.
One of those opened normally but the edges became dark and dry. Monstera Deliciosa is an elegant beauty of a houseplant loved so much around the world for its iconic looks. This is especially true if you have a variegated Monstera they burn incredibly easily.
Sometimes a new plant will have these spots if it wasnt given quality care while at the store or greenhouse.
The other two just seemed to dry off and become black. Monstera deliciosa developed weird black spots on the edge of one leaf. Leaf spot and root rot. Its in a well drained pot standing on top of a rock bottom wetted to give the plant moisture.