Resources I like to use while designing, feel free to suggest other resources.
Vectorstock
Decent amount of free vectors
Vecteezy
Non-bright vectors, pleasing to the eyes
Pixabay Illustrations
Not necessarily vectors, but amazing art
unDraw
Can customise theme even before downloading. Also includes hand-drawn illustrations.
Freepik
Wonderful UI & loads of free vectors
Flaticon
Subset of Freepik & has more options
Freepik
Lesser options, but nice icons
Feather
Simple, beautiful open source collection
Iconmonstr
Boldly graphic icons in a few different styles
The Noun Project
Search for a noun, get a free symbol or icon
Endless Icons
Free icon library
Material Icons
Delightful, beautifully crafted symbols for common actions and items
Svg Porn
High quality SVG logos
Blobmaker
Don't like blobs, but this is nice
Fonts in Use
Fonts available to download, with examples of use
Type Goodness
Mostly ideas, but fonts mentioned
Type Everything
Amazing fonts, allows testing too, mostly paid fonts though
FontPair
Awesome Google font combinations
Canva Font Combinations
Font pairing generator
Pexels
Loads of options
Unsplash
Richer in color, and has collections
StockSnap
Beautiful, but very limited options
Gratisography
Easy to browse categories, high resolution and free
PicJumbo
Beautiful and free
Little Visuals
Free, high resolution images
SplitShire
Exclusive, free stock photos
Dribble
Amazing for everything, especially typography, branding and illustrations
Web Designs are very stock vector based
Pinterest
Amazing boards to follow
Behance
Links directly with Adobe CC
Eat Sleep Draw
Amazing Illustrations & Cartoons, some are funny too
Open Peeps
Human Illustrator generator
DrawKit
Hand Drawn Illustrations
Blush
Illustrations for everyone
Humaaans
Mix-&-match illustrations of people with a design library
Control
108 customizable illustrations
Open Doodles
A Free Set of Sketchy Illustrations
Absurd Design
Absurd illustrations that make sense
The Best Designs
Interesting layouts
Portfolio
Cool portfolio pages
UI Design Daily
Daily design inspiration for UI
Book Cover Archive
Cool designs
Carbon
Code snippets with styling options for presentation
Power to the Poster
Posters on current world(mostly US) issues
The Vintage Posters
Original vintage posters to buy or be inspired by
Happy Hues
Superb color palettes
BrandColors
Check out the exact colors that major brands use
0 to 255
Find the perfect color variation
Khroma
Uses AI to learn which colors you like and creates palettes
Colorsinspo
All in one resource for finding colors
Eva
Complimentary colour generator powered by deep learning
Pigment
A unique way to generate fresh and vibrant colors
Brand Colors
Biggest collection of official brand color codes
Stark
Color-blind simulator and contrast checker
Color Safe
Build accessible colour combinations
90 Colors
A free collection of accessible color themes
Color Oracle
Free color blindness simulator
PiXimperfect
Very thorough, detailed and interesting
Letsgettoit
Cool effects and detailed explanation
Blue Lightning TV
First place I learnt PS from, still active even now
COOPH
Interesting ideas and easy to understand
Adorama
Quick, short tips
Jordan Matter
Cool shots on the go
Design Taxi
Freebies from different companies, has good Adobe tips too
The Pattern Library
Some of these make nice backgrounds
Canva
This isn't design