As of right now, Fields of type Enum have FieldType.Option, and we can use them as such, e.g. do FieldRef.OptionMembers() to get the names of the available enumerated values as a comma-separated string, as with Options. Hopefully this is future-proof...!

There are also the following methods on FieldRef, from which we can loop the available names/ordinals and do dynamic stuff that way. It's a shame they don't return Lists for easier use. Having to loop manually is boilerplate

EnumValueCount
GetEnumValueCaption
GetEnumValueCaptionFromOrdinalValue
GetEnumValueName
GetEnumValueNameFromOrdinalValue
GetEnumValueOrdinal

Could we get versions of these methods that return lists, so we needn't loop, and can instead do e.g.

if not FieldRef.GetEnumValueOrdinals.Contains(SomeInteger) then Error(SomeError);

i.e. can you please add:
FieldRef.GetEnumValueCaptions(): List of [Text]
FieldRef.GetEnumValueNames(): List of [Text]
FieldRef.GetEnumValueOrdinals(): List of [Integer]