This is a list of tools I use on mspabooru, maybe some of you will also find them useful.

Tampermonkey
https://www.tampermonkey.net
You need this chrome extension to install userscripts.

Linkify++
https://greasyfork.org/en/scripts/4255-linkify-plus-plus
This userscript lets you click on source links, or any link that isn't directly clickable.

Booru mass uploader
https://github.com/Seedmanc/Booru-mass-uploader
This userscript lets you upload many images in bulk. Because mspabooru isn't supported by default, you can add it by following the pattern of the existing @include lines. Just remember to tag and source them all later!
Edit 9/5: This userscript doesn't work if the filename contains emojis.

gallery-dl
https://github.com/mikf/gallery-dl
A program that lets you easily download artwork. When downloading from Tumblr, it can filter for certain tags.

cool thread idea!
i make heavy use of the saucenao extension for sourcing art.
https://saucenao.com/tools/