I’ve purchased a few HP Elitedesk 800 G3 Minis (refurbished) for about $125 on Amazon. They even come with Windows 10 if you’re looking for that. They’re a deal considering the Pi’s extra expenses like power, case, storage, etc.
Of course if you deck out a Pi 4 with a SSD and a fan, it'll come much closer to the G3 Mini in terms of power consumption.
When you throw in m.2, lots of ram, all that IO eats power. So the minimum idle power creeps up. Arm boards too.
Not sure about the <=G3 and >=G7, but the G4 and G5 have the issue. The G6 seems to have the fan attached more firmly, but I've never tested one in a quiet room.
Lenovo has M700, M75q (AMD) and a bunch others ranging from thin client to workstation performance.
Generally new ones are awesome at about $700 but older ones are absolutely capable for upgrading ram, disk, wifi whatever. there are modules for up to 10g and other things too. Servethehome on YouTube has a bunch of guides.