https://godotengine.org/ - Godot is a popular choice for its relative ease compared to Unity and Unreal Engine. Recommend Godot to start off if you are okay with learning programming.

https://www.renpy.org/ - Visual Novel engine, used to make a surprising amount of VNs found in itch.io. Has a relative amount of flexibility if you learn some programming.

https://textadventures.co.uk/quest/ - Another text-based engine to make interactive story games. Is open-source and is even available to use directly on the web-browser.

https://www.lexaloffle.com/pico-8.php - Sprite based "fantasy console" where the entire coding, and playing can take place in a console.

https://ledoux.itch.io/bitsy - Bitsy is a web-based game-making tool, great for making small and short narrative based games.

Visual

https://www.aseprite.org/ - Great pixel art tool for $20 usd. It is also open-source so you can build it yourself.

https://www.piskelapp.com/ - Web-based pixel art tool. The simplest tool to use here.

https://lospec.com/ - Palettes and tutorials and everything for pixel/voxel art.

https://opengameart.org/ - Get pre-made assets here available to use here.

https://game-icons.net/ - UI and Icons available for free

Audio

https://boscaceoil.net/ - Free and easy-to-use music maker

https://pixwlk.itch.io/petaporon - Ultra simple, minimalistic music maker.

https://freesound.org/ - Sound database

https://www.zapsplat.com/ - Sound database

Working in Teams

https://trello.com - Free and easy-to-use project management to communicate and delegate work

https://aggie.io - Draw-together app to brainstorm together

https://unity.com/unity/features/collaborate - If your team is working in Unity, consider looking up Unity Collaborate.

CATEGORY	AI TOOL/PRODUCT LINK
TEXT/CODE	https://chat.openai.com/	Free/Paid
TEXT/CODE	https://www.safurai.com/	Free/Paid
NPCs	https://www.convai.com/	Free/Paid
ART	https://ommer-lab.com/research/latent-diffusion-models/	Free/Paid
ART	https://www.midjourney.com/home/	Free/Paid
ART	https://leonardo.ai/	Free/Paid
SPEECH TO TEXT	https://openai.com/research/whisper	Free/Paid
SOUNDS/MUSIC	https://app.uberduck.ai/	Free/Paid
SOUNDS/MUSIC	https://www.descript.com/	Free
SOUNDS/MUSIC	https://www.aiva.ai/	Free/Paid
ANIMATION	https://cascadeur.com/	Free/Paid
ANIMATION/MOCAP	https://www.deepmotion.com/	Free/Paid
OBJECT DATABASE	https://objaverse.allenai.org/	Free
OPEN SOURCE GOODIES	https://huggingface.co/tasks	Free/Paid

List of game engines:

Game engine	Description
GameMaker 8	Not perfect, may have issues, but the easiest to use.
OneLua	One of the best Lua interpreters for PSP and PS Vita.
Lutro	Very crossplatform, simple version of Love2D.
PlayLua	Crossplatform Lua game engine, for access ask developer.
Gen7 Engine	Crossplatform Python block based game engine. I have almost no info about this one.
Stardust Celeste	Crossplatform C++ and Lua game engine that never will get docs.
QuickGame	Stardust Celeste with less features, BUT has docs.
RenPy	Visual novel engine. An old renpy player. There are new better ones, but devs gatekeep them.
ONScripter	Another visual novel engine. I have no idea how stable it is.
PGM CE	Unpopular chinese visual novel engine made for PSP (don't check History_exe's twitter).
Quest Soft Player	Very crossplatform text game engine. Literally, text. It is cool though.
Adventure Game Studio	Easy to use, stable, but not very advanced.
Adventure Maker	Very old game engine that has official PSP port, not advanced at all.
RPG Maker 2000/2003	An old player. Not perfect, may have issues, old, but easy to use. You also can use EasyRPG player.
Godot 2	Has bugs, if version 3 doesn't work, try version 2.
Virtools	Pray to god for this to work.
Dow!	Lua programming on PSP itself. Funny.