1. Learn the basics: Manga

The Idiot's Guide to Editing Manga:
https://www.insidescanlation.com/etc/the-idiots-guide-to-editing-manga/guide/main

Anonblack's Typesetting guide:
https://mangadex.org/title/08e1f85a-bb12-4fe4-aec5-0d7a80b3a261/anonblack-s-typesetting-guide


1.1. Free Image editing software
GIMP:
https://www.gimp.org/


1.2. Sites for fonts
Soon(tm)


2. Online dictionaries and databases

JapanDict:
https://www.japandict.com/

Japanese game and manga text sound effect (SFX) database:
https://gist.github.com/UserUnknownFactor/093a2296c5a4d9ef7b404728ebde94a3


3. Online Japanese keyboards/Kanji finder (When OCR fails)

Lexilogos:
  -Hiragana:
  https://www.lexilogos.com/keyboard/hiragana.htm

  -Katakana:
  https://www.lexilogos.com/keyboard/katakana.htm

JapanDict:
  Kanji(radical search):
  https://www.japandict.com/radicals/search

  Kanji(drawing search):
  https://www.japandict.com/kanjidraw

4a. In app(SillyTavern) 2nd opinions:
DeepL:
https://www.deepl.com/en/chrome-extension
https://www.deepl.com/en/edge-extension
https://www.deepl.com/en/firefox-extension


4b. In app grammar checker:
LanguageTool:
https://languagetool.org/

00. Misc.
All-in-one toolbox(sugoi toolkit):
https://www.patreon.com/mingshiba/about
(only available in the middle of every month(15th-16th) unless you pay)