p8dl - Carts Downloader - Python - Downloads cartridges into the correct folder (looks at your config.txt).

Tiled2Pico-8 Exporter/Importer + Sprite editor

pico2png - Spritesheet extraction written in perl.

r/pico8 - Spritesheets and tools for the Pico-8 Palette

14 votes and 4 comments so far on reddit

Pico8Utils - Compilation of lua scripts based on the unix philosophy for working with .p8 files.

picotool - Tools and Python libraries for manipulating Pico-8 game files.

Pico-8 Carts Downloader - Bash - Downloads cartridge from the BBS (single cart, whole index or dump your favourited entries) & rename them according to their metadata.

p8 responsive webplayer transform - Python script that makes your HTML export page responsive.

pico-8 color palette

PICO-8.ttf + variants

pico-test - PICO-8 testing framework.

Lib-Pico8 - A Pico-8 library of useful common functions.

pico8-missing-builtins - Provides Lua built-in functions to pico8.

P8Coder - A programming tool that replaces the lua code in pico-8 cartridges (p8) with the code you write in P8Coder.

Pico-Kit - An opinionated collection of Pico-8 helpers that make it easier to get going. Adds OOP, better debugging, and physics.

picoDeploy - Deploy Pico-8 carts as standalone applications on desktop (Electron) and mobile (Ionic).

pico8Grunt - A build system for pico8 games, using gruntjs.

PICO-EC - A tiny scene-entity-component library created for the PICO-8 fantasty console.

PICO-Tween - A small library of tweening/easing functions for use in the PICO-8 fantasy console, inspired by Robert Penner's easing functions.

p8 - A dependency manager and build tool. Lets you share code/sprites,

MIDI to PICO-8 - A tool to convert MIDI files to PICO-8 music.

midi2pico - A MIDI to PICO-8 converter.

Denote by Jenny Schmidt

Midi demake tool for pico 8

Custom HTML template

PICO-8 fillp tool by Sean

Helper for creating pico 8 fillp patterns

Depict by Jenny Schmidt

Image demake tool for pico 8

picoCAD by Johan Peitz

A tiny modeller for tiny models

pico8-deploy - An easy way to export and deploy PICO-8 projects to itch.io

yap8b - Build tool for creating pico carts from multiple source files.