https://github.com/simonmichael/quickbench - Easily time one or more commands with one or more executables and show tabular results
https://github.com/simonmichael/shelltestrunner - Easy, repeatable testing of CLI programs/commands
https://github.com/simonmichael/hledger - Robust, fast, intuitive plain text accounting tool with CLI, TUI and web interfaces
https://github.com/haskell-game/fungen - A lightweight, cross-platform, OpenGL-based 2D game engine in Haskell
https://haskell-game.dev - a small selection of the many games written in Haskell
https://haskell-via-sokoban.nomeata.de - Haskell via Sokoban
https://lhbg-book.link - Learn Haskell by building a blog generator
https://github.com/input-output-hk - the Cardano blockchain and Daedalus wallet
https://github.com/jgm/pandoc - Universal markup converter (already mentioned above)
https://github.com/simplex-chat/simplex-chat - secure messaging platform
https://www.libhunt.com/l/haskell - more projects...
that's a good list to look at into for inspiration, thanks!
Let me try covering interesting for many people (hopefully including you!):
Start: https://github.com/topics/haskell
https://github.com/koalaman/shellcheck
https://github.com/PostgREST/postgrest
https://github.com/hadolint/hadolint
https://github.com/jaspervdj/patat
https://github.com/smallhadroncollider/taskell
https://github.com/fosskers/aura
https://github.com/HuwCampbell/grenade
https://github.com/Haskell-Things/ImplicitCAD
https://github.com/lettier/gifcurry - GIF editor
https://github.com/2mol/pboy - pdf management utility
https://github.com/ChrisPenner/rasa - Extremely modular text editor built in Haskell
https://github.com/samtay/tetris - terminal interface for Tetris
https://github.com/mattgreen/hython - Haskell-powered Python 3 interpreter
https://github.com/lettier/movie-monad - A free and simple to use video player made with Haskell.
https://github.com/dbousamra/hnes - NES Emulator written in Haskell