| Monad | MonadLib, MonadLib.Monads |
| MonadPlus | MonadLib, MonadLib.Monads |
| MonadT | MonadLib, MonadLib.Monads |
| mapAndUnzipM | MonadLib, MonadLib.Monads |
| mapM | MonadLib, MonadLib.Monads |
| mapM_ | MonadLib, MonadLib.Monads |
| mplus | MonadLib, MonadLib.Monads |
| msum | MonadLib, MonadLib.Monads |
| mzero | MonadLib, MonadLib.Monads |