Blender

Cursor and origin dot

# Move 3d cursor to the center
Shift + C

# Move Object origin to the 3d cursor
Top Left -> Object button -> Set origin -> Origin to 3d cursor

Scaling

# Scale inwards/outwards only
Alt + s

# Scale skin modifier vertices
Alt + a

Extruding

# Extrude to cursor and keep the alignment
- Press numbad 1 to view from the from side
- Move cursor to the desired position
- Ctrl + mouse right click

# Extrude multiple faces at once
Edit mode -> face mode -> Select multiple faces ( hold shift )
Alt + e -> Extrude individual faces

Selecting

# Select whole parts individual from an object ( For example only leaves on a tree object )
Hover over the object part -> Press 'L'

# De-select
Hover over the object part -> Shift + L

# Select everything around the object ( For example every side of a square ) ( Loop select )
Hover over the object -> Alt + left click

# Select everything around the object to the other direction
Hover over the object near a edge -> Alt + left click

# Select faces by 'painting' over them
Hover over some faces -> Press 'C' -> Click mouse left-> paint over other faces

# De-select faces by 'painting' over them
Hover over some faces -> Press mouse wheel -> paint over other faces

# Ring select ( select all of the edges around an object)
Alt -> Ctrl -> left click an edge

# Loop select ( select all edges up and downwards that are connected )
Alt -> Left click an edge

# Select the shortest path to another edge
Edge mode -> Click an adge -> Hold Ctrl and click another edge somewhere else

# Lasso select
Ctrl + mouse right

# Select more nearby faces with a button press
Select a face -> Ctrl and + sign to grow selection, - to decrease selection ( numpad )

# Select random
Go to face mode for example -> Ob the top click 'Select' button -> select random

# Select similar
Click a face -> Shift + G

# Select faces pointing to the same direction ( good for example to add snow on top of things)
Click a face -> Shift + G -> Normal -> ( increase threshold at the bottom popup )

# Select every other face
Face mode -> hover over an object and press L to select all -> F3 -> search for 'checker deselect' -> press enter

# Knife select
Press 'K' -> Knife out a shape and press enter

Misc

# Duplicate an object
Click object -> Shift + D

# Toggle X-ray
Alt + Z

# Hide an object
Press 'H'

# Unhide an object
Alt + H

# Set individual origin
Press '.' (dot) -> individual origin

# Snap to center of a face
Hold down Ctrl

# Create a low poly rock
Subdivide ( Ctrl + 3 for example ) -> Edit mode -> Press 'O' -> vertex mode -> Move verteces around -> Object mode -> Add decimate modifier -> Lower ratio

# Flatten faces
Edit -> Preferences -> Addons -> Search loop tools -> enable
Select multiple faces -> F3 -> Search for flatten

# Select between normal and global orientation
Press ',' ( comma )

# Fill holes
Select whole object with 'L' -> Press 'F'

# Add edges
Select 2 vertices -> Press 'J'

# Triangulate a face
Select a Face -> Ctrl + T

# Remove edges from a face
Select multiple faces -> Press 'X' -> Dissolve edges

# Bridge objects together
Select a face from each object -> F3 -> Bridge edge loops

# Separate loose parts in to their own objects
Edit mode -> hover over the object -> Press 'A' to select all -> Press 'P' -> By loose parts

# Merge loose parts in to same object
Slecet all objects -> Ctrl + J

# Enable auto mirroring
Object mode -> Edit -> Preferences -> Addons -> auto mirror -> enable
Press 'N' -> click AutoMirror in the popup top right

# Create land shape fast
Add plane -> Resize bigger -> Ctrl + 5 -> On the subdivide menu -> Press Simple -> Press Apply -> Go to edit mode to see the effects
To add more subdivides -> Object mode -> Ctrl + 2 -> On the subdivide menu -> Press Simple -> Press Apply -> Go to edit mode to see the effects
Press 'C' and select some faces -> Press 'O' to enable proportional editing -> Press 'S' to scale upwards

# Flip selection ( Select everything that is not currently selected )
Ctrl + I

# De-select eveything with a specific color on a color palette
In UV Editing window click douple arrow icon top right -> Press 'B' -> Shift box select the color that we want to de-select

Problem fixing

# Merge all vertices on object
Press 'A' to select all -> Press 'M' -> by distance

# Flip faces
Alt + N -> Flip

# Flip all faces on a object
Face mode -> Select all -> Alt + N -> Recalculate outside

# Mis-aligned vertices
Top middle tool bar -> snap options -> Vertex
click vertex -> move on desired axis -> Hold Ctrl -> point to a vertex that is in right alignment

# If scaling is messed up or inset is not uniformed ( to check press 'N' -> Item -> Scale: everything should be 1 )
Object mode -> Ctrl + A -> Scale

# Move objects to collection
Press 'M' -> create new or select existing onge