code/__HELPERS/abstract_types.dm 
| /proc/get_abstract_types | Returns a list of all abstract typepaths for all datums |
|---|---|
| /proc/valid_subtypesof | Like subtypesof, but automatically excludes abstract typepaths |
| /proc/get_abstract_branch_descendants | Returns a list of concrete types under abstract sub-branches of root |
| /proc/valid_direct_subtypesof | Like valid_subtypesof(), but excludes concrete descendants of abstract sub-branches |
| /proc/valid_direct_typesof | Like valid_typesof(), but excludes concrete descendants of abstract sub-branches |