Here's some stuff I made, just userscripts for now
Userscripts
These userscripts all update automatically
E621 Artist page URL icons
Adds images to Artist page URLs (ex. Twitter logo next to Twitter link, etc.)
E621 upload tags copy-paste (BETA)
Copy and paste tags between multiple e621 upload pages. Useful for uploading alternate versions of an image at the same time (don't forget to set the parent post though)
Furry sites Antitroll image types
FurAffinity and FurryNetwork have (had?) a bad habit of downscaling images to 1280x***, convert the images to JPG, but still keep the original image MIME type and extension. This warns you when it happens.
Works standalone or with the imageData extension.
FurAffinity error page to Wayback Machine
Link to The Wayback Machine on FurAffinity error pages.
FurAffinity warn on megapixel limit
Warn when a FurAffinity post might have been downscaled due to the new megapixel limits.
Kheina always show explicit results
Always include explicit results in Kheina searches.
SoFurry open full-size in new tab
Add a button to open a SoFurry post's full-size image in a new tab.
Here's some stuff I didn't make but I find useful
Userscripts
Idem's sourcing Suite
Not maintained anymore, but still useful for the quick "upload to e621" button.
DonovanDMC has an updated version but I prefer using the base with a FA fix from me
RE621
Makes this site 100x better, I cannot live without it.
None of my userscripts conflict with it.
Extensions
FoxReplace
Find-and-Replace for Firefox. Privileged users and above don't need this as they can use tag scripts .
imageData
Displays image resolution, file type, and file size when hovering on an image.
Pixiv Toolkit
Convert ugoira (animated images) to GIF or APNG and download them
Random Bookmark from folder (Chrome, Firefox)
I have a lot of bookmarks, what can I say.
Updated