Colors:

Coolors | Color Hunt | Color Hex

Audio: 

SoundBible.com | freesound | Youtube Audio Library

Assets:

OpenGameArt.org | Kenney 

3D Models: 

TURBOSQUID | Poly

Textures: 

Texture Haven 

Fonts:

DaFont | Google fonts | Font Squirrel

Images: 

Pixabay | Unsplash

Story Generator:

Seventh Sanctum | Steampunk Random Story Generator

Management:

Trello | Milanote