i3lock is the default screen lock that comes with i3wm

they are other options, I simply list them. Make your own opinions.

i3lock fancy

https://github.com/meskarune/i3lock-fancy

i3lock with more feature:

This is an i3lock bash script that takes a screenshot of the desktop, blurs the background and adds a lock icon and text

i3lock-color

https://github.com/Raymo111/i3lock-color

many features, mostly a configurable version of i3lock.

betterlockscreen

https://github.com/betterlockscreen/betterlockscreen

fast and sweet looking lockscreen for linux systems with effects!

xsecurelock

https://github.com/google/xsecurelock

X11 screen lock utility with security in mind

xss-lock

https://bitbucket.org/raymonad/xss-lock

Use external locker as X screen saver.

slock

https://tools.suckless.org/slock/

• suckless
• so very basic, but that's the idea of suckless movements.

Further readings

Once again, interesting further readings are available on Arch Linux wiki pages:

• https://wiki.archlinux.org/title/Session_lock