Beginner

Derek makes awesome product tutorials.  If you want to make a product animation and need to model some products, he has the best Tutorials.

This tutorial shows you how to model, texture and animate these cosmetics. 

How to do claymation in BLender

SouthernShotty on youtube has really embraced the claymation look.

 This is another awesome style Claymation by SouthernShotty

This is always a good feature in your sci fi animations, a HUD.

Beginner

He creates a nice looking motion graphic using simple shapes.

He makes some shapes, and animates them.  Nice design for the HUD. 

Places to get 3d objects  Some are free

You can scan objects using an Apple Ipad pro with Lidar.

You can scan objects using a camera and Photo scanning software.

Kit Bashing was first started by buying real model kits and making new things out of all the various parts.  Like having legos from a bunch of kits and making something new.

As Blender makes it's new asset manager system, Kit Bashing will become easier and more fun.  

Several plugins already have this functionality such as the kit ops plugin.  (very fun and fast to make for example sci fi props)