Writing
DeepL
Probably the best translator that is currently available, additionally for some time it also does text rephrase.
LanguageTool
Open-source spelling and grammar checking tool with additional text rephrasing tools.
Etherpad
Framepad
Image
Squoosh
The best photo optimization tool I’ve I used, a lot of formats available including the fresh new JPGXL and AVIF. It’s very simple and intuitive. For batch photo it has CLI tool, which is sadly no longer developed, but still works
Photopea
Actually viable Photoshop alternative, supports most of the basic tools. Being and web app creates some limitations, but otherwise for most no-professionals should be good enough.
Video
Data
Grist
FOSS cloud based datasheet, including some advanced features as well python scripting
LiberaForms
Free and privacy respecting form tool, doesn’t requite account to submit answers,
SM Hub
mixpost
erxes
Analytics
redditmetis
Reddit user statistic tool
https://shadowban.yuzurisa.com/
Twitter shadowban checking tools