Or tools that have been recommended to me and I need to put them somewhere 1) so I don't forget 2) to explore/play with them.

Find Tags on Tumblr - I'm intrigued!
Marginalia Search to find noncommercial nontracking websites
Teclis - Non-commercial Web Search
Ecosia is an internet search that plants trees
NameCheckr.Com to check see if anyone's already taken an anon pseud you want anywhere on the internet
Firefox Multi-Account Containers for easy switching between pseuds between tabs

Canva's elements are free to use for your own designs without any attribution, not stand-alone though
Wikimedia Commons Category: Public Domain
NASA images (all gov images) are all public domain
The Public Domain Review is similar to Canva - free to use as long as you transform things
Flickr Commons is fun historial images is public domain clip art. I worry a little bit this site isn't that well-moderated, that some users are uploading Creative Commons - Attribution Required licensed images not full-on Public Domain ones. Hopefully I'm being paranoid.
British Public Library released >1 million images into the public domain via Flickr Commons! So cool
Wikipedia's List of Digital Library Projects sheesh gotta explore!
Public Domain Icons by apancik on GitHub
Public Domain Vectors
Notion promotes itself as the height of productivity but I'm putting it under data analysis for now because I use it to organize, filter, view data
SlidesGo - Free Google Slides themes and Powerpoint templates (a lot of these use the illustration sites linked below, esp flaticon)
Aspose - Converts your powerpoints to HTML (used for my panels in the Events tab) - hand drawn illustration library - standard nice icons
MS 365 Powerpoint's free icons, frequently updated, always need to edit the icon though - 'audience interaction made easy'
The Noun Project is $40 a year to allow you access to all their icons, changing icon colors, and not having to cite them (eh I don't mind citing) for animated icons? idk. Free version only has about 1000 available but hey still cool
PureWriter+ Desktop to match the PureWriter+ app for phones/tablets - I love this app for writing!
GoodNotes. This app is for tablets with styluses. It's amazing for proofreading; marking up your own writing in red is so satisfying. I paid the $30 for the suite of premium options after having the free version for a month and loving it.
LeanPub a publishing platform that came recommended in a thread on masto that I found super interesting.
Duck Prints Press is another publisher whose roots are in fandom and fanfiction's Just Delete Me
Digital Shred Workshop - Library Guides at Penn State University
Mailinator is for testing automated mailbox tasks for developers mostly but it allows you to create a disposable email with which to sign up for junk (I haven't tested this one myself yet tho). - Search 5.8 billion images used to train popular AI art models. - Enter your email or phone to see if it's been found in any data breaches. False negatives have happened with this site; practice safe online security no matter what!
Unredacter - if you use pixelation to redact, you're not gonna have a good time

Calibre is the best ebook organizer ever.
Library Extension allows you to see if your local library has the materials you're looking at on, Goodreads, etc. For Chrome, Firefox, and Edge.
AlternativeTo.Net offers FOSS alternatives to any program (literally a software thesaurus it's amazing!!!)
The Internet Archive
r/LibbyLibby on Reddit shares library cards
List of Public Libraries with Non-Resident Borrowing
Free Media Heck Yeah's wiki and also their new website
Ocean of PDF has moved domains sometimes but it's been around for ages
Z-Library (or if that didn't work, Go To zlibrary might help
LibriVox | free public domain audiobooks

Finding Books to Read
The Storygraph - love the pie charts and analytics! Not that social but that's okay
Whumpy Book Recommendations
Recommend Me A Book - read the first page of a book without knowing its title or author to see if you like it.

Weird Niches
tenochtitlan.thomaskole - anybody up for exploring ancient Tenochtitlan in a 3D environment designed in Blender and published to this website? A+ fascinating
Masterpost of Free and Full Shakespeare Adaptations on tumblr
Radiooooo isn't really a dark library but pick a country and a decade and listen to some international music
Human Anatomy for Artists Search Helper

Students and Researchers: - CORE-GPT which offers explicit references to 34 million published scientific research papers,,,
Worldcat - NGO dedicated to "open access to quality research journals published in developing countries" - research papers in economics
Smithsonian Open Access
TinEye Reverse Image Search

Here's a list of tools I use (or aspire to use!) re: 3D design and printing:

Libraries of 3D Models to Explore:

Combatting AI Scraping

Glaze is a way to protect artists from generative AI
Nightshade is from the same team over at Chicago University, tricking generative AI and protecting copyright

Photo Editing (in Browser)

Photopea is advanced image editor meant to dupe Photoshop as much as possible.
Pixlr is another image editor I've used before but I feel like its free online version has gone downhill

Image Generation & Editing allows for a lot of fun creative images and designs. I've taught a couple classes on it at my library.
PhotoFunia is where the 80s retro & vaporwave poster generators come from. There's a lot more - very fun.
removebg is a really simple website that'll remove the background of any jpg image and turn it into a png
Pixel It will convert any picture to pixel art. So cool gotta try this out asap...
Glitterboo will make small elements shiny and awesome - lil glittery glowing golden snakey snake incoming :D

Audio Editing
Online music/voice separator based on neural nets

Video Editing

DaVinci Resolve is my primary video editor. I really love my DaVinci Resolve Speed Editor
OpenShot Video Editor
Renegade Bindery's Resources are AMAZING; the community on Discord is the most friendly and functional mega-sized server I've ever seen
Bookbinder formats PDFs for bookbinding 😍
r/Fanbinding and r/BookBinding on Reddit - glue advice! What an awesome site haha