diff --git a/library/STMContainers/Bimap.hs b/library/STMContainers/Bimap.hs
--- a/library/STMContainers/Bimap.hs
+++ b/library/STMContainers/Bimap.hs
@@ -12,8 +12,8 @@
   lookup2,
   focus1,
   focus2,
-  foldM,
   null,
+  stream,
 )
 where
 
@@ -137,7 +137,10 @@
 focus2 s b (Bimap m1 m2) = (inline focus1) s b (Bimap m2 m1)
 
 -- |
--- Fold all the associations.
-{-# INLINABLE foldM #-}
-foldM :: (r -> (a, b) -> STM r) -> r -> Bimap a b -> STM r
-foldM s r = Map.foldM s r . m1
+-- Stream associations.
+-- 
+-- Amongst other features this function provides an interface to folding 
+-- via the 'ListT.fold' function.
+{-# INLINE stream #-}
+stream :: Bimap a b -> ListT STM (a, b)
+stream = Map.stream . m1
diff --git a/library/STMContainers/HAMT.hs b/library/STMContainers/HAMT.hs
--- a/library/STMContainers/HAMT.hs
+++ b/library/STMContainers/HAMT.hs
@@ -32,3 +32,7 @@
 {-# INLINE null #-}
 null :: HAMT e -> STM Bool
 null = Nodes.null
+
+{-# INLINE stream #-}
+stream :: HAMT e -> ListT STM e
+stream = Nodes.stream 0
diff --git a/library/STMContainers/HAMT/Nodes.hs b/library/STMContainers/HAMT/Nodes.hs
--- a/library/STMContainers/HAMT/Nodes.hs
+++ b/library/STMContainers/HAMT/Nodes.hs
@@ -6,6 +6,7 @@
 import qualified STMContainers.SizedArray as SizedArray
 import qualified STMContainers.HAMT.Level as Level
 import qualified Focus
+import qualified ListT
 
 
 type Nodes e = TVar (WordArray.WordArray (Node e))
@@ -151,3 +152,10 @@
       Nodes ns -> foldM step acc' (Level.succ level) ns
       Leaf _ e -> step acc' e
       Leaves _ a -> SizedArray.foldM step acc' a
+
+stream :: Level.Level -> Nodes e -> ListT.ListT STM e
+stream l =
+  lift . readTVar >=> ListT.fromFoldable >=> \case
+    Nodes n -> stream (Level.succ l) n
+    Leaf _ e -> return e
+    Leaves _ a -> ListT.fromFoldable a
diff --git a/library/STMContainers/Map.hs b/library/STMContainers/Map.hs
--- a/library/STMContainers/Map.hs
+++ b/library/STMContainers/Map.hs
@@ -8,8 +8,8 @@
   delete,
   lookup,
   focus,
-  foldM,
   null,
+  stream,
 )
 where
 
@@ -71,12 +71,6 @@
     f' = (fmap . fmap . fmap) (\v -> k `seq` v `seq` (k, v)) . f . fmap associationValue
 
 -- |
--- Fold all the items of a map.
-{-# INLINE foldM #-}
-foldM :: (a -> (k, v) -> STM a) -> a -> Map k v -> STM a
-foldM s a (Map h) = HAMT.foldM s a h
-
--- |
 -- Construct a new map.
 {-# INLINE new #-}
 new :: STM (Map k v)
@@ -96,3 +90,12 @@
 {-# INLINE null #-}
 null :: Map k v -> STM Bool
 null (Map h) = HAMT.null h
+
+-- |
+-- Stream associations.
+-- 
+-- Amongst other features this function provides an interface to folding 
+-- via the 'ListT.fold' function.
+{-# INLINE stream #-}
+stream :: Map k v -> ListT STM (k, v)
+stream (Map h) = HAMT.stream h
diff --git a/library/STMContainers/Multimap.hs b/library/STMContainers/Multimap.hs
--- a/library/STMContainers/Multimap.hs
+++ b/library/STMContainers/Multimap.hs
@@ -8,8 +8,9 @@
   delete,
   lookup,
   focus,
-  foldM,
   null,
+  stream,
+  streamByKey,
 )
 where
 
@@ -108,18 +109,6 @@
             (r,) . bool Focus.Keep Focus.Remove <$> Set.null set
 
 -- |
--- Fold all the items.
-{-# INLINE foldM #-}
-foldM :: (a -> (k, v) -> STM a) -> a -> Multimap k v -> STM a
-foldM f a (Multimap m) = 
-  Map.foldM f' a m
-  where
-    f' a' (k, set) = 
-      Set.foldM f'' a' set
-      where
-        f'' a'' v = f a'' (k, v)
-
--- |
 -- Construct a new multimap.
 {-# INLINE new #-}
 new :: STM (Multimap k v)
@@ -139,3 +128,20 @@
 {-# INLINE null #-}
 null :: Multimap k v -> STM Bool
 null (Multimap m) = Map.null m
+
+-- |
+-- Stream associations.
+-- 
+-- Amongst other features this function provides an interface to folding 
+-- via the 'ListT.fold' function.
+stream :: Multimap k v -> ListT STM (k, v)
+stream (Multimap m) = 
+  Map.stream m >>= \(k, s) -> (k,) <$> Set.stream s
+
+-- |
+-- Stream values by a key.
+streamByKey :: Association k v => k -> Multimap k v -> ListT STM v
+streamByKey k (Multimap m) =
+  lift (Map.lookup k m) >>= maybe mempty Set.stream
+
+
diff --git a/library/STMContainers/Prelude.hs b/library/STMContainers/Prelude.hs
--- a/library/STMContainers/Prelude.hs
+++ b/library/STMContainers/Prelude.hs
@@ -19,6 +19,14 @@
 -------------------------
 import Data.Hashable as Exports (Hashable(..))
 
+-- transformers
+-------------------------
+import Control.Monad.Trans.Class as Exports
+
+-- list-t
+-------------------------
+import ListT as Exports (ListT)
+
 -- custom
 -------------------------
 import qualified Debug.Trace.LocationTH
diff --git a/library/STMContainers/Set.hs b/library/STMContainers/Set.hs
--- a/library/STMContainers/Set.hs
+++ b/library/STMContainers/Set.hs
@@ -8,8 +8,8 @@
   delete,
   lookup,
   focus,
-  foldM,
   null,
+  stream,
 )
 where
 
@@ -71,12 +71,6 @@
       (fmap . fmap . fmap) (const (HAMTElement e)) . s . fmap (const ())
 
 -- |
--- Fold all the elements.
-{-# INLINE foldM #-}
-foldM :: (a -> e -> STM a) -> a -> Set e -> STM a
-foldM f a = HAMT.foldM (\a -> f a . elementValue) a . hamt
-
--- |
 -- Construct a new set.
 {-# INLINE new #-}
 new :: STM (Set e)
@@ -96,3 +90,12 @@
 {-# INLINE null #-}
 null :: Set e -> STM Bool
 null = HAMT.null . hamt
+
+-- |
+-- Stream elements.
+-- 
+-- Amongst other features this function provides an interface to folding 
+-- via the 'ListT.fold' function.
+{-# INLINE stream #-}
+stream :: Set e -> ListT STM e
+stream = fmap elementValue . HAMT.stream . hamt
diff --git a/stm-containers.cabal b/stm-containers.cabal
--- a/stm-containers.cabal
+++ b/stm-containers.cabal
@@ -1,7 +1,7 @@
 name:
   stm-containers
 version:
-  0.1.4
+  0.2.0
 synopsis:
   Containers for STM
 description:
@@ -63,7 +63,9 @@
     -- data:
     hashable < 1.3,
     -- control:
-    focus > 0.1.0 && < 0.2,
+    list-t >= 0.2.4 && < 0.3,
+    focus >= 0.1.2 && < 0.2,
+    transformers >= 0.3 && < 0.5,
     -- debugging:
     loch-th == 0.2.*,
     placeholders == 0.1.*,
@@ -89,11 +91,12 @@
     free >= 4.6 && < 4.10,
     mtl == 2.*,
     QuickCheck == 2.7.*,
-    HTF == 0.11.*,
+    HTF == 0.12.*,
     -- data:
     hashable < 1.3,
     -- control:
-    focus > 0.1.0 && < 0.2,
+    list-t >= 0.2.4 && < 0.3,
+    focus >= 0.1.2 && < 0.2,
     -- debugging:
     loch-th == 0.2.*,
     placeholders == 0.1.*,
@@ -115,14 +118,15 @@
     APITests.hs
   build-depends:
     QuickCheck == 2.7.*,
-    HTF == 0.11.*,
+    HTF == 0.12.*,
     stm-containers,
     -- debugging:
     loch-th == 0.2.*,
     placeholders == 0.1.*,
     -- general:
     base-prelude == 0.1.*,
-    focus > 0.1.0 && < 0.2,
+    list-t >= 0.2.4 && < 0.3,
+    focus >= 0.1.2 && < 0.2,
     unordered-containers == 0.2.*,
     free >= 4.6 && < 4.10,
     mtl == 2.*,
@@ -153,7 +157,8 @@
     criterion == 0.8.*,
     -- data:
     text < 1.2,
-    focus > 0.1.0 && < 0.2,
+    list-t >= 0.2.4 && < 0.3,
+    focus >= 0.1.2 && < 0.2,
     hashable < 1.3,
     hashtables == 1.1.*,
     containers == 0.5.*,
@@ -185,7 +190,8 @@
     mwc-random-monad == 0.7.*,
     -- data:
     text < 1.2,
-    focus > 0.1.0 && < 0.2,
+    list-t >= 0.2.4 && < 0.3,
+    focus >= 0.1.2 && < 0.2,
     unordered-containers == 0.2.*,
     hashable < 1.3,
     stm-containers,
@@ -218,7 +224,8 @@
     -- data:
     containers >= 0.5.2 && < 0.6,
     text < 1.2,
-    focus > 0.1.0 && < 0.2,
+    list-t >= 0.2.4 && < 0.3,
+    focus >= 0.1.2 && < 0.2,
     unordered-containers == 0.2.*,
     hashable < 1.3,
     stm-containers,