Premade things you can use for your games!

LemmaSoft CC Forum (lots of things in here)

https://itch.io/c/484684/visual-novel-assets-tutorials-and-tools

http://www.vita-chi.net/sec/voi/hora/english.htm

https://potat0master.itch.io/

Sprites:

https://liah0227.itch.io/

https://itch.io/c/2006928/my-free-visual-novel-characters-for-your-use

https://itch.io/c/228580/assets-i-created

https://itch.io/c/1115123/new-style-free-to-use-assets

https://banya.itch.io/free-sprites-vn

https://itch.io/c/698965/yume-series-free-to-use-assets

https://sutemo.itch.io/

https://chibi785.itch.io/

https://cucurbitapepo.itch.io/girl-sprites-for-visual-novel

https://dejinyucu.itch.io/

https://minttydrops.itch.io/

https://duokhay.itch.io/

http://tokudaya.net/index.html

Backgrounds:

https://itch.io/c/2006931/my-free-visual-novel-backgrounds-and-items-for-your-us...

https://katy133.itch.io/vn-asset-pack

https://tidalblossoms.itch.io/free-outdoor-visual-novel-backgrounds

https://noranekogames.itch.io/yumebackground

https://chibi785.itch.io/cafe-background

https://vision-renders.itch.io/

https://konett.itch.io/misc-visual-novel-background

https://lemmasoft.renai.us/forums/viewtopic.php?f=52&t=17302

https://www7b.biglobe.ne.jp/~osumashi/free_bg.html

Other images:

https://opengameart.org/

https://unsplash.com/

GUI:

https://thaumaturge-art.itch.io/assets-fantasy-ui

https://tofurocks.itch.io/renpy-gui-template

https://loudeyes.itch.io/dating-sim-ui-pack

https://florassence.itch.io/

https://lunalucid.itch.io/free-character-creation-template-for-renpy

Music and SFX:

https://freemusicarchive.org/genre/Soundtrack/

https://cross-couloir.itch.io/beats-by-cross-couloir

https://lemmasoft.renai.us/forums/viewtopic.php?t=48443

https://lemmasoft.renai.us/forums/viewtopic.php?t=54072

https://lunalucid.itch.io/free-creative-commons-bgm-collection

https://mayragandra.itch.io/freeemotionalpianomusic

https://soundimage.org/

https://dreamer173.bandcamp.com/

https://www.sougetsu-on.net/

http://asobeat.com/

https://musmus.main.jp/english.html