moltype controlled vocabulary?
There is this "Controlled vocabulary for /mol_type qualifier" page created by the International Nucleotide Sequence Database Collaboration in 2013.  It says the allowed values are:


  "genomic DNA", "genomic RNA", "mRNA", "tRNA", "rRNA", "other RNA", "other DNA", "transcribed RNA", "viral cRNA", "unassigned DNA", "unassigned RNA"


I found this as the second result of a Google search on moltype vocabulary.