The type must be a reference type in order to use it as parameter 'TEntity' in the generic type or method 'DbSetTEntity'

A Generic class, which receives the type of enum :

public class EnumTable<TEnum>
    where TEnum : struct
{
    public TEnum Id { get; set; }
    public string Nome { get; set; }
    public string Descricao { get; set; }

    protected EnumTable() { }

    public EnumTable(TEnum enumType)
    {
        if (!typeof(TEnum).IsEnum)
        {
            throw new Exception($"Argumento inválido do tipo {typeof(TEnum)}");
        }

        Id = enumType;
        Nome = enumType.ToString();
        Descricao = enumType.GetEnumDescription<TEnum>();
    }

    public static implicit operator EnumTable<TEnum>(TEnum enumType) => new EnumTable<TEnum>(enumType);
    public static implicit operator TEnum(EnumTable<TEnum> status) => status.Id;
}

Two extension methods, to get the description and make the seed:

      public static string GetEnumDescription<TEnum>(this TEnum item)
=> item.GetType()
       .GetField(item.ToString())
       .GetCustomAttributes(typeof(DescriptionAttribute), false)
       .Cast<DescriptionAttribute>()
       .FirstOrDefault()?.Description ?? string.Empty;



  public static void SeedEnumValues<T, TEnum>(this IDbSet<T> dbSet, Func<TEnum, T> converter)
where T : class
  {
          Enum.GetValues(typeof(TEnum))
            .Cast<object>()
            .Select(value => converter((TEnum)value))
            .ToList()
            .ForEach(instance => dbSet.AddOrUpdate(instance));
  }

Your enum :

public enum MeuEnum
{
   [Description("Em Aberto")]
    Aberta = 1,

   [Description("Fechado")]
    Fechada = 4,

   [Description("Aguardando alguma coisa")]
    Aguardando = 5
}

Your class, inheriting the generic class, informing your enum:

public class MeuEnumClass: EnumTable<MeuEnum>
{
    public MeuEnumClass(MeuEnum enumType) : base(enumType)
    {

    }

    public MeuEnumClass() : base() { } //deve ser definido o construtor padrão para o EF
}

Your DbSet:

public DbSet<MeuEnumClass> Status { get; set; }

Override the EF configuration class Seed method:

protected override void Seed(SeuDbContext context)
{
    context.Status.SeedEnumValues<MeuEnumClass, MeuEnum>(@enum => new MeuEnumClass(@enum));
}

Ready. Create migration and update the database.