Bookmark and Citation

EasyBib
Zotero
Citefast
EndNote
Noodle Tools
Cite This For Me

Taking Notes

EverNote
OneNote
Dropbox Paper
Google Keep
Bear
Standard Notes

Organization Tools

Trello
Any Do
Todoist
Microsoft To Do
Tick Tick
My Study Life

Calculators

Wolfram
Mathway
Symbolab
Desmos
MathPapa
eMathHelp

Miscellaneous

PDFSam