diff --git a/src/algebra/io.js b/src/algebra/io.js
index 460dbde..47cfb7a 100644
--- a/src/algebra/io.js
+++ b/src/algebra/io.js
@@ -55,5 +55,9 @@ export class IO extends Algebra(Monad) {
   run() {
     return this._effect()
   }
+
+  toString() {
+    return `IO(${this._effect})`
+  }
 }
 
diff --git a/src/algebra/list.js b/src/algebra/list.js
index b2dd033..95dbda5 100644
--- a/src/algebra/list.js
+++ b/src/algebra/list.js
@@ -70,6 +70,10 @@ class Empty extends Interfaces {
   isEmpty() {
     return true
   }
+
+  toString() {
+    return `List(Empty)`
+  }
 }
 
 /** @template T */
@@ -172,6 +176,10 @@ class Element extends Interfaces {
       []
     )
   }
+
+  toString() {
+    return `List(${this.toArray()})`
+  }
 }
 
 class TypeRef {
diff --git a/src/algebra/option.js b/src/algebra/option.js
index 7ebf79c..ffb6b58 100644
--- a/src/algebra/option.js
+++ b/src/algebra/option.js
@@ -85,6 +85,10 @@ export class Some extends Interfaces {
   reduce(f, init) {
     return f(init, this.#value)
   }
+
+  toString() {
+    return `Some(${this.#value})`
+  }
 }
 
 /** @template T */
@@ -151,6 +155,10 @@ export class None extends Interfaces {
   reduce(_f, init) {
     return init
   }
+
+  toString() {
+    return 'None'
+  }
 }
 
 /**
diff --git a/src/algebra/result.js b/src/algebra/result.js
index 1445f3b..f9fcfc2 100644
--- a/src/algebra/result.js
+++ b/src/algebra/result.js
@@ -140,6 +140,10 @@ export class Ok extends Interfaces {
   bimap(f, _g) {
     return /** @type {Result<T2, E2>} */ (this.map(f))
   }
+
+  toString() {
+    return `Ok(${this.#value})`
+  }
 }
 
 /**
@@ -257,6 +261,10 @@ export class Err extends Interfaces {
   bimap(_f, g) {
     return /** @type {Result<T2, E2>} */ (err(g(this.#value)))
   }
+
+  toString() {
+    return `Err(${this.#value})`
+  }
 }
 
 /**