This page is just a public amalgamation of all the tools I've come across for my own reference made public.

Web Dev

Absolute Beginner Guides

Whiteheartrainbowsoul's Web Revival Glossary: Covers common vocabulary used in web revival spaces.

Melonking's Website Guide: Melonking covers making your first page, and also things to keep in mind while website building.

Mdn Web Docs: Extensive web documentation that covers both HTML/CSS basics and how to get started with a website.

W3 Schools: Extensive documentation on the basics of HTML/CSS.

Sadgrl.online/learn: Directory of tips and tutorials by sadgrl.

BadHTML: A visual example of a website that does not follow web standards. Includes obsolete HTML and Bad HTML/CSS.

Linkrot: What is it and How to Avoid It

Web Accessibility

What I've Learned About Web Accessibility as a Dyslexic, Sighted, Mouse User by Solaria

Accessibility Fundamentals Overview

WCAG and supporting documents explain how to make content more accessible to people with disabilities.

Alt-texts Ultimate Guide

World Wide Web Consortium (W3C)- Develops standards and guidelines to help everyone build a web based on the principles of accessibility, internationalization, privacy and security.

The Front-End Checklist

Lighthouse Viewer

Cheatsheets

HTML Cheatsheet

CSS Cheatsheet

Javascript Cheatsheet

Generators

HTML Cheatsheet: HTML Cheatsheet.

Open Source Libraries

PlayHTML

Tools

Can I Use: Check what features are supported by specific browsers.

Markup Validator: Checks codes for errors and warnings.

Github: Cloud-based service for software development and version control using Git, allowing developers to store and manage their code.

Codepen: Share HTML/CSS/Javascript snippets and run them online.

Jsfiddle: Share HTML/CSS/Javascript snippets and run them online.

Broken Link Checker: Checks websites for broken links.

XML Sitemaps: Generate XML Sitemaps.

Test webpages on different screen resolutions

Convert large blocks of text to html code

Dynamic Dummy Image Generator

RSS Time Stamp Generator

Embed Google Photos

Free Image Host

Colorffy: Generate your custom color variables with our easy-to-use CSS and SCSS Variables Generator to easily create and manage your CSS and SCSS custom variables.

Code Snippets

Sadgrl.online/learn/: Directory of tips and tutorials by sadgrl.

Fc2counter Visitor Counter Code

Updating Top Nav Bar

Updating SideBar

RV's free Javascript/DHTML effects

Free Hosted Scripts

Allison's carrd

Password Protect HTML Pages

Rarebit - Webcomic Template Built in HTML and JavaScript

Library of Ready-to-use, Cross-browser Animations

Templates

HTML5 Templates

Matthewjamestaylor: Offers the bare bones code for literally any layout you could possibly want

Tutorials

Build a Theme Switcher for Your Website with JavaScript

Games as Learning Tools

A keyboard accessibility horror game.

Elara is a game that teaches you how to code.

Game to help learn javascript.

RSS

Convert email newsletters into Atom feeds

Mangadex RSS Generator

RSSBox