YouTube

General DIY

DIY Perks (slick designs)
Nerdforge (LED, sculpture, book building)
TecH BoyS ToyS (cool DIY projects)
Tech Ingredients (indepths projects)
YetAnotherTechChannel (cool home projects)

3D Printing

Overview

CNC Kitchen (general 3D printing channel with engineering in mind)
Thomas Sanladerer (general 3D printing channel)
Maker's Muse (design, tips, reviews)
3D Printing Nerd (general channel)

Beginner

Architects3DP (Cura and DIY printer)
CHEP (Ender3 tutorials and tips)
Teaching Tech (best channel to learn 3D printer mods)

Advanced

Chris Riley (advance 3D printing, controller boards/firmware)
Proper Printing (cool developments)
Lars Christensen (fusion360)
Design Prototype Test (analysis, tech)

Woodwork

DIY Creators (general)
Marius Hornberger (general)
Seejanedrill (DIY 101, good tips)
Get Hands Dirty (general)

Computers

Trends & Analysis

AdoredTV (trends
Coreteks (trends)

Computer Science

Computerphile (academic)
ExplainingComputers (general, reviews, trends)
Level1Techs (trends, reviews, linux)
Linus Tech Tips (reviews, computer build)
OzTalksHW (budget builds, reviews)
Programming with Mosh (python)
Siraj Raval (AI, deeplearning, beginner)
ThioJoe (for Windows users, beginner)

Electronics

Andreas Spiess (wireless communication)
GreatScott (general electronics)
ElectroBoom (funny general electricity)
Anak Agung Duwi Arsana (general electronics)
Jeremy Fielding (electricity, motors)

General Science

3Blue1Brown (maths)
Knowing Better (history, general)
Numberphile (maths)
PBS Space Time (astrophysics)
Minutephysics (physic):
SciShow (short scientific news)
Dr. Becky (astrophysics)
SciShow Space (short astrophysics)
It's Okay To Be Smart (popular sciences)
Vsauce (best popular science)

General Engineering

Curious Droid (general engineering)
Megaprojects (general engineering)
Real Engineering (great general channel)