Animate tiny 8x8 people and things in Tiny Animator! (comes with Pico-8 sprites exporter)
(it should work ok here on the BBS but prefer downloading the cart and loading it in Pico-8, it'll work better)
With this tool you can create your own animations, using the base humanoid model or your own (instructions further below), put an imported skin on it and export the generated sprites, either to a png or to your clipboard as formatted sprites that you can directly paste into your Pico-8 sprite-sheet. And you can also save and load your animations using the clipboard!
EDIT: it seems, the use of the clipboard on the BBS is pretty buggy so if you wanna use the saving, importing and exporting features, please download the cart (right click on "cart" in bottom-left corner of the player and "save link as...").
The best way to understand the editor should be to use it but here are a few things you may want to know to use saves, skins and custom models:
You can import skins to apply to your animation. To do this, simply make a skin based on the shape your using (the humanoid one by default) in Pico-8. Then ctrl+C your 8x8 tile containing the skin, get back in Tiny Animator, ctrl+V and hit one of the free skin buttons.
You can also use a custom base! Be warned, doing so will reset the rest of the editor. Like for the skins, you want to draw your base in the sprite-sheet and then copy it to the animator and hit the base button. If you want to have your base all linked up like the default one, you simply gotta make sure each pair of pixels which should be connected have consecutive colors (e.g.: 4 and 5). Prefer to go from the color 1 and up with each link. The pixel of lowest color will serve as anchor point to move all connected points as one.
'fpf' is Frames Per animation Frames. It's the number of Pico-8 frames (running at 30 fps) between each animation frame. 3 or 4 are generally good values but you may want a 6 or higher for rougher animations. (you can also play your animations backward with negative numbers)
[End of instructions]