What are the best tools to use to create 2D graphics and animations for Unity?

Question

2D

You need to make 2d graphics for the game under the unity.
So the question arose which tool is best suited for this.
Of course, to draw the sprites themselves, use Photoshop (probably).
But for animation I'm breaking my head, I don't catch the essence.
As I understand it, for 2D games, they mainly use frame-by-frame animation, which, in turn, is done in three ways. Either all sprites are drawn by hand (as I understood it is popular in pixel art), or with the help of drag-and-drop tools for layers of individual parts of the character (they twist the leg there, they bring the arm in there, and like a gait turned out), or fully using skeletal animation, which functions perfectly, but ofk is somehow more difficult because you still need to set up all the keys, but at the output you can do animation a lot and quickly.
Here I can't understand
1. What exactly to choose? According to the idea, it all depends on how much I want to use graphics in the game, if there is not a lot of animation, then it’s enough to manually make the sprites frame by frame, and that’s it.
And if I want to do a lot of animation, and high quality, then it's better to use the skeletal animation method, right?
2. Why can't skeletal animation be fully used in the game, why is it only frame-by-frame cut, because the animation is not so perfect, the question is in resource costs? How big is the difference? Or is skeletal animation in 3D games also kind of frame-by-frame? I have a problem with understanding this question (((
3. Let's say I want to work out my character with a lot of animation, so I choose a skeletal one, so that it turns out soundly, which tool is best for this?
As I understand it, programs for 3d modeling are also great for 2d, the same blender, 3dsmax, cinema 4d, maya, or cool and expensive programs specifically for 2d animation, spine and anime studio, what are the main criteria used to select a tool for creating 2d animations. And again, it seems like in Yunka itself you can also do the same frame-by-frame skeletal animation using mecanim (I just haven’t figured it out yet, you can make bones directly in it, or be sure to port the model from 3d editors), so why use other programs if you can do without means in Yunka?
Plus, there are paid assets for the same unit for skeletal animation
. What to choose? Difficult, 2nd day google dig and in the ru segment there is very little information about this

Answer 1

Skeletal animation is definitely easier to produce and takes less memory, but, for example, you can’t do such animation with it:
Frame-by-frame animation allows you to draw anything, it’s easier to add effects and change material properties, you can even cram 3D animation into sprites. On the other hand, with skeletal animation it's easier to make smooth animations, it's easier to iterate. I would advise you to try with it, since the unit provides the official plugin for free . Of course, if you're a super-duper-quick artist or you're making a fighting game, then it might be better to use frame-by-frame animation.
I advise you to watch the presentations on the links below, this will allow you to better understand the difference in the workflow:
Animation Style and Process for Broken Age
Making Fluid and Powerful Animations For Skullgirls