Urizen 1Bit Tileset - 5500+ free 12x12 tiles

You can show link to project, like "This game is using Urizen tileset (link)". But anyway CC0 license doesn't force you to do it.

Most frameworks have some form of class that lets you handle spritesheets with methods for displaying the needed frames and thus animations. 

For example in python & pygame: https://www.pygame.org/wiki/Spritesheet

In Godot you use a Sprite2D Node and a AnimationPlayer node to use sprite sheets directly. 

In Rust and Bevy you load in your sprite sheet and then layout it: https://bevy.org/examples/2d-rendering/sprite-sheet/

let texture = asset_server.load("textures/rpg/chars/gabe/gabe-idle-run.png");     
let layout = TextureAtlasLayout::from_grid(UVec2::splat(24), 7, 1, None, None);    
let texture_atlas_layout = texture_atlas_layouts.add(layout);        
let animation_indices = AnimationIndices { first: 1, last: 6 };