I installed i3 for archlinux and i could not start applications with “$mod+d”.
It was really stupid of me, but i nevertheless decided to drop some lines on that.
TL/DR: Install dmenu with “sudo pacman -S dmenu”
Turns out: when you install i3 on arch, it only installes i3 and the absolutely necessary packages for that. dmenu isnt necessary.
So i wasted about 10 minutes googleing the problem until i found some old comment in a forum and then installed dmenu.