diff --git a/src/hz.erl b/src/hz.erl
index 2014adb..d255c24 100644
--- a/src/hz.erl
+++ b/src/hz.erl
@@ -1546,6 +1546,7 @@ opaque_type_name(Name)            -> binary_to_list(Name).
 
 builtin_typedefs() ->
     #{"unit" => {[], {tuple, []}},
+      "void" => {[], {variant, []}},
       "hash" => {[], {bytes, [32]}},
       "option" => {["'T"], {variant, [{"None", []},
                                       {"Some", [{var, "'T"}]}]}},
@@ -1589,7 +1590,15 @@ builtin_typedefs() ->
                                          {"ChannelSnapshotSoloTx", [address]},
                                          {"ContractCreateTx", [integer]},
                                          {"ContractCallTx", [address, integer]},
-                                         {"GAAttachTx", []}]}}
+                                         {"GAAttachTx", []}]}},
+      "Chain.tx" => {[], {record, [{"paying_for", {"option", ["Chain.paying_for_tx"]}},
+                                   {"ga_metas", {list, ["Chain.ga_meta_tx"]}},
+                                   {"actor", address},
+                                   {"fee", integer},
+                                   {"ttl", integer},
+                                   {"tx", "Chain.base_tx"}]}},
+      "MCL_BLS12_381.fr" => {[], {bytes, [32]}},
+      "MCL_BLS12_381.fp" => {[], {bytes, [48]}}
      }.
 
 % Type preparation has two goals. First, we need a data structure that can be
@@ -1701,12 +1710,6 @@ normalize_opaque_type(T, Types) -> normalize_opaque_type(T, Types, true).
 % FIXME detect infinite loops
 % FIXME detect builtins with the wrong number of arguments
 % FIXME should nullary types have an empty list of arguments added before now?
-% These types represent some FATE variant:
-% Chain.ttl, AENS.pointee, AENS.name, AENSv2.pointee, AENSv2.name,
-% Chain.ga_meta_tx, Chain.paying_for_tx, Chain.base_tx,
-%
-% And then MCL_BLS12_381.fr represent bytes(32), and MCL_BLS12_381.fp
-% represents bytes(48).
 normalize_opaque_type(T, _Types, IsFirst) when is_atom(T) ->
     % Once we have eliminated the above rewrite cases, all other cases are
     % handled explicitly by the coerce logic, and so are considered normalized.
@@ -2715,6 +2718,7 @@ param_test() ->
 
 obscure_aaci_test() ->
     Contract = "
+        include \"Set.aes\"
         contract C =
             entrypoint options(): option(int) = None
             entrypoint fixed_bytes(): bytes(4) = #DEADBEEF
@@ -2741,6 +2745,11 @@ obscure_aaci_test() ->
             entrypoint pointee2(x): AENSv2.pointee = AENSv2.DataPt(x)
             entrypoint name2(x, y, z): AENSv2.name = AENSv2.Name(x, y, z)
 
+            entrypoint fr(x): MCL_BLS12_381.fr = x
+            entrypoint fp(x): MCL_BLS12_381.fp = x
+
+            entrypoint set(): Set.set(int) = Set.new()
+
     ",
     {ok, AACI} = aaci_from_string(Contract),
 
@@ -2757,15 +2766,18 @@ obscure_aaci_test() ->
     {ok, {_, {"Chain.paying_for_tx", _, {variant, _}}}} = aaci_lookup_spec(AACI, "paying_for"),
     {ok, {_, {"Chain.ga_meta_tx", _, {variant, _}}}} = aaci_lookup_spec(AACI, "ga_meta_tx"),
     {ok, {_, {"Chain.base_tx", _, {variant, _}}}} = aaci_lookup_spec(AACI, "base_tx"),
-    % Why do the other types here get hard coded in the compiler, but this one
-    % doesn't? Should we be getting stdlib types from includes?
-    %{ok, {_, {"Chain.tx", _, {variant, _}}}} = aaci_lookup_spec(AACI, "tx"),
+    {ok, {_, {"Chain.tx", _, {record, _}}}} = aaci_lookup_spec(AACI, "tx"),
 
     {ok, {_, {"AENS.pointee", _, {variant, _}}}} = aaci_lookup_spec(AACI, "pointee"),
     {ok, {_, {"AENS.name", _, {variant, _}}}} = aaci_lookup_spec(AACI, "name"),
     {ok, {_, {"AENSv2.pointee", _, {variant, _}}}} = aaci_lookup_spec(AACI, "pointee2"),
     {ok, {_, {"AENSv2.name", _, {variant, _}}}} = aaci_lookup_spec(AACI, "name2"),
 
+    {ok, {_, {"MCL_BLS12_381.fr", _, {bytes, [32]}}}} = aaci_lookup_spec(AACI, "fr"),
+    {ok, {_, {"MCL_BLS12_381.fp", _, {bytes, [48]}}}} = aaci_lookup_spec(AACI, "fp"),
+
+    {ok, {[], {{"Set.set", [integer]}, _, {record, [{"to_map", _}]}}}} = aaci_lookup_spec(AACI, "set"),
+
     ok.
 
 name_coerce_test() ->
@@ -2786,4 +2798,11 @@ name_coerce_test() ->
     NameFate = {variant, [3], 0, {AddrFate, TTLFate, #{<<"myname">> => PointeeFate}}},
     try_coerce(Name, NameSoph, NameFate).
 
+void_coerce_test() ->
+    % Void itself can't be represented, but other types built out of void are
+    % valid.
+    {ok, NonOption} = annotate_type({"option", ["void"]}, builtin_typedefs()),
+    try_coerce(NonOption, {"None"}, {variant, [0, 1], 0, {}}),
+    {ok, NonList} = annotate_type({list, ["void"]}, builtin_typedefs()),
+    try_coerce(NonList, [], []).