diff --git a/src/node/handler.rs b/src/node/handler.rs
index 50254e3..1c86bc4 100644
--- a/src/node/handler.rs
+++ b/src/node/handler.rs
@@ -15,14 +15,14 @@ pub enum NodeHandler {
 impl NodeHandler {
     pub fn run(&self, inputs: Vec<f64>, passed_x: f64) -> f64 {
         match self {
-            NodeHandler::Number { number } => number.clone(),
-            NodeHandler::Function {
+            Self::Number { number } => number.clone(),
+            Self::Function {
                 function,
                 name,
                 max_args,
             } => function(inputs),
-            NodeHandler::Variable => passed_x,
-            NodeHandler::Empty => inputs[0],
+            Self::Variable => passed_x,
+            Self::Empty => inputs[0],
         }
     }
 }
diff --git a/src/node/node_modifier.rs b/src/node/node_modifier.rs
index 1a40ac4..148e152 100644
--- a/src/node/node_modifier.rs
+++ b/src/node/node_modifier.rs
@@ -9,6 +9,9 @@ const TYPE_CHANGE_PROBABILITY: u8 = 10;
 
 pub enum NodeManipulationError {
     TooMuchChildren(Node),
+    NotEnoughChildren,
+    ProtectedEmpty,
+    IndexOutOfRange(usize),
 }
 impl fmt::Display for NodeManipulationError {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
@@ -17,6 +20,9 @@ impl fmt::Display for NodeManipulationError {
             "{}",
             match self {
                 NodeManipulationError::TooMuchChildren(node) => "Too much children",
+                NodeManipulationError::ProtectedEmpty => "Empty node is protected",
+                NodeManipulationError::NotEnoughChildren => "Not enough children",
+                NodeManipulationError::IndexOutOfRange(index) => "Index out of range",
             }
         )
     }
@@ -31,11 +37,43 @@ pub struct NodeModifier<'a> {
 
 impl<'a> NodeModifier<'a> {
     fn get_standard_pool() -> (Vec<NodeHandler>, Vec<fn(f64) -> f64>) {
-        let standard_function_mutation: Vec<NodeHandler> = vec![NodeHandler::Function {
-            name: "Sine".to_string(),
-            function: |inputs| inputs[0].sin(),
-            max_args: Some(1),
-        }];
+        let standard_function_mutation: Vec<NodeHandler> = vec![
+            NodeHandler::Function {
+                name: "sin".to_string(),
+                function: |inputs| inputs[0].sin(),
+                max_args: Some(1),
+            },
+            NodeHandler::Function {
+                name: "cos".to_string(),
+                function: |inputs| inputs[0].cos(),
+                max_args: Some(1),
+            },
+            NodeHandler::Function {
+                name: "sum".to_string(),
+                function: |inputs| inputs.iter().sum(),
+                max_args: None,
+            },
+            NodeHandler::Function {
+                name: "-".to_string(),
+                function: |inputs| -inputs[0],
+                max_args: Some(1),
+            },
+            NodeHandler::Function {
+                name: "product".to_string(),
+                function: |inputs| inputs.iter().product(),
+                max_args: None,
+            },
+            NodeHandler::Function {
+                name: "exp".to_string(),
+                function: |inputs| inputs[0].powf(inputs[1]),
+                max_args: Some(2),
+            },
+            NodeHandler::Function {
+                name: "1/".to_string(),
+                function: |inputs| 1f64 / inputs[0],
+                max_args: Some(1),
+            },
+        ];
         let standard_number_mutation: Vec<fn(f64) -> f64> = vec![
             |x| x * 4f64,
             |x| x / 4.0f64,
@@ -91,6 +129,27 @@ impl<'a> NodeModifier<'a> {
         self.picked_node.children.push(node);
         Ok(())
     }
+    pub fn remove_node(
+        &mut self,
+        specified_index: Option<usize>,
+    ) -> Result<(), NodeManipulationError> {
+        if self.picked_node.children.len() == 0 {
+            return Err(NodeManipulationError::NotEnoughChildren);
+        }
+        match specified_index {
+            Some(index) => {
+                if self.picked_node.children.len() <= index {
+                    return Err(NodeManipulationError::IndexOutOfRange(index));
+                }
+                self.picked_node.children.remove(index);
+                Ok(())
+            }
+            None => {
+                self.picked_node.children.remove(0);
+                Ok(())
+            }
+        }
+    }
 
     pub fn insert_node(
         &mut self,
@@ -113,6 +172,7 @@ impl<'a> NodeModifier<'a> {
 
     pub fn mutate_node(&mut self) {
         if random_range(0..TYPE_CHANGE_PROBABILITY) == TYPE_CHANGE_PROBABILITY - 1 {
+            self.change_node_type(None);
         } else {
             match &self.picked_node.handler {
                 NodeHandler::Number { number } => {
@@ -144,4 +204,39 @@ impl<'a> NodeModifier<'a> {
             }
         }
     }
+    pub fn change_node_type(&mut self, to: Option<NodeHandler>) {
+        self.picked_node.handler = to.unwrap_or(self.get_random_handler());
+    }
+    pub fn get_random_handler(&self) -> NodeHandler {
+        let picked = random_range(0..4);
+
+        if picked == 0 {
+            NodeHandler::Number {
+                number: random_range(0.0..=1e8f64),
+            }
+        } else if picked == 1 {
+            self.function_mutation_pool[random_range(0..self.function_mutation_pool.len())].clone()
+        } else if picked == 2 {
+            NodeHandler::Variable
+        } else {
+            NodeHandler::Empty
+        }
+    }
+    pub fn get_random_node(&self) -> Node {
+        let handler = self.get_random_handler();
+        Node {
+            children: vec![],
+            handler: handler.clone(),
+            max_children_count: match handler {
+                NodeHandler::Number { number } => Some(0),
+                NodeHandler::Function {
+                    name,
+                    function,
+                    max_args,
+                } => max_args,
+                NodeHandler::Variable => Some(0),
+                NodeHandler::Empty => Some(1),
+            },
+        }
+    }
 }