Here is a list of yet undocumented values for the GetOtion / SetOption method of the NotesDatabase class.

GetOption(82) / SetOption(82,true) = Enable Compress document data
GetOption(81) / SetOption(81,true) = Use DAOS

Use DAOS also created a new field $DAOS in the NotesIcon design note if the field is not available and update the field value to 1 (enabled) or 0 (disabled) when the field is already present

Both are only available with ODS 51

GetOption(74) / SetOption(74,true) = still unknown, but adds O to $Flags

And here are a few database properties that can be get / set by modifying the $Flags field programmatically

$Flags = I = Inherit operating system theme from Notes preferences (ODS 51)
$Flags = q = Compress Database Design
$Flags = C = Allow connections to external databases using DCRs

Finally, if you want to find out, if the “Enable enhanced HTML Generation” property is enabled, check if field $AllowPost8HTML is available in the NotesIcon design note. The according theme is stored in $DBTheme.