diff --git a/Yesod/Form/Fields.hs b/Yesod/Form/Fields.hs
--- a/Yesod/Form/Fields.hs
+++ b/Yesod/Form/Fields.hs
@@ -42,6 +42,7 @@
     , OptionList (..)
     , mkOptionList
     , optionsPersist
+    , optionsPersistKey
     , optionsPairs
     , optionsEnum
     ) where
@@ -86,6 +87,8 @@
 
 import Data.Attoparsec.Text (Parser, char, string, digit, skipSpace, endOfInput, parseOnly)
 
+import Yesod.Persist.Core
+
 defaultFormMessage :: FormMessage -> Text
 defaultFormMessage = englishFormMessage
 
@@ -510,6 +513,31 @@
     return $ map (\(Entity key value) -> Option
         { optionDisplay = mr (toDisplay value)
         , optionInternalValue = Entity key value
+        , optionExternalValue = toPathPiece key
+        }) pairs
+
+-- | An alternative to 'optionsPersist' which returns just the @Key@ instead of
+-- the entire @Entity@.
+--
+-- Since 1.3.2
+optionsPersistKey
+  :: (YesodPersist site
+     , PersistEntity a
+     , PersistQuery (YesodPersistBackend site (HandlerT site IO))
+     , PathPiece (Key a)
+     , RenderMessage site msg
+     , PersistEntityBackend a ~ PersistMonadBackend (YesodDB site))
+  => [Filter a]
+  -> [SelectOpt a]
+  -> (a -> msg)
+  -> HandlerT site IO (OptionList (Key a))
+
+optionsPersistKey filts ords toDisplay = fmap mkOptionList $ do
+    mr <- getMessageRender
+    pairs <- runDB $ selectList filts ords
+    return $ map (\(Entity key value) -> Option
+        { optionDisplay = mr (toDisplay value)
+        , optionInternalValue = key
         , optionExternalValue = toPathPiece key
         }) pairs
 
diff --git a/Yesod/Form/Functions.hs b/Yesod/Form/Functions.hs
--- a/Yesod/Form/Functions.hs
+++ b/Yesod/Form/Functions.hs
@@ -99,13 +99,18 @@
     (x, _, _) <- ask
     return $ liftM snd x
 
+-- | Converts a form field into monadic form. This field requires a value
+-- and will return 'FormFailure' if left empty.
 mreq :: (RenderMessage site FormMessage, HandlerSite m ~ site, MonadHandler m)
-     => Field m a
-     -> FieldSettings site
-     -> Maybe a
+     => Field m a           -- ^ form field
+     -> FieldSettings site  -- ^ settings for this field
+     -> Maybe a             -- ^ optional default value
      -> MForm m (FormResult a, FieldView site)
 mreq field fs mdef = mhelper field fs mdef (\m l -> FormFailure [renderMessage m l MsgValueRequired]) FormSuccess True
 
+-- | Converts a form field into monadic form. This field is optional, i.e.
+-- if filled in, it returns 'Just a', if left empty, it returns 'Nothing'.
+-- Arguments are the same as for 'mreq' (apart from type of default value).
 mopt :: (site ~ HandlerSite m, MonadHandler m)
      => Field m a
      -> FieldSettings site
@@ -155,6 +160,7 @@
         , fvRequired = isReq
         })
 
+-- | Applicative equivalent of 'mreq'.
 areq :: (RenderMessage site FormMessage, HandlerSite m ~ site, MonadHandler m)
      => Field m a
      -> FieldSettings site
@@ -162,6 +168,7 @@
      -> AForm m a
 areq a b = formToAForm . liftM (second return) . mreq a b
 
+-- | Applicative equivalent of 'mopt'.
 aopt :: MonadHandler m
      => Field m a
      -> FieldSettings (HandlerSite m)
@@ -218,7 +225,7 @@
                   _           === _         = False  -- in order to avoid timing attacks.
     return ((res', xml), enctype)
 
--- | Similar to 'runFormPost', except it always ignore the currently available
+-- | Similar to 'runFormPost', except it always ignores the currently available
 -- environment. This is necessary in cases like a wizard UI, where a single
 -- page will both receive and incoming form and produce a new, blank form. For
 -- general usage, you can stick with @runFormPost@.
diff --git a/yesod-form.cabal b/yesod-form.cabal
--- a/yesod-form.cabal
+++ b/yesod-form.cabal
@@ -1,5 +1,5 @@
 name:            yesod-form
-version:         1.3.1
+version:         1.3.2
 license:         MIT
 license-file:    LICENSE
 author:          Michael Snoyman <michael@snoyman.com>