Alternative kernels: Zen, XanMod, Liquorix and hardened

In short: Besides the distribution’s default kernel there are variants with other goals: responsiveness for desktop and games (Zen, XanMod, Liquorix), more security (hardened) or real time.

In more detail: They are based on the mainline kernel and add patches and different settings.

In detail

• linux-zen: offered on Arch, tuned for responsiveness and desktop.
• XanMod: with scheduler adjustments and higher network performance, as packages for Debian/Ubuntu.
• Liquorix: Debian-based, aimed at desktop timing and games.
• linux-hardened: extra security features, lower compatibility.
• linux-lts: keeps a long-term kernel ready as a fallback.
• linux-rt: real-time kernel, see Real-time Linux (PREEMPT_RT).
• CachyOS and others: distributions with their own optimised kernels and schedulers (BORE, EEVDF).
• Caution: the gain is often small. Problems can arise with third-party drivers (NVIDIA, VirtualBox).

See also: Compiling your own kernel, Kernel versions and release cycle