For me it's PeppermintOS.
I started my Linux adventure a few years ago, and haven't owned a Windows PC since.
I currently use Arch on my main rig, and I wanted to install Linux on two old laptops that I found laying around in my house
I then remembered the first distro I ever used, which is PeppermintOS, and I was amazed at the latest updates they released.
They even have a mini ISO now to do a net-install with no bloat, with a Debian or Devuan base.
Sadly, I believe the founder passed away a few years ago, which is why I was really happy to see the continuation of this amazing project.
OpenWrt
I'm considering replacing my router with a software router and have been comparing a few options.
I was having a lot of difficulty getting 10Gbps through opnsense. Even after tuning a bunch of tunables, I was only getting 3Gbps or so, with no fancy features like IPS/IDS enabled. It was just a basic out-of-the-box config with my current home network as the "WAN" and a small lab network as a LAN. Something (NAT maybe?) seems to be single-threaded as it was hitting 100% of one core on a six-core i5-9500 (which should be more than powerful enough for this).
While researching I learnt that OpenWrt has an x86-64 build you can run on a computer. I thought it was only for regular routers.
Flashed OpenWrt to a USB stick and tried it instead of opnsense. Out of the box I got full 10Gbps speed, using less CPU power than 3Gbps used in opnsense (~15% per core across all cores). The base system is fast and light, only using 15MB of disk space and less than 100MB RAM. That makes sense given it's designed to run on routers, but in an era where a lot of software is very bloated, it's nice to see lightweight software that does its job with barely any overhead.