What are some alternatives?
When comparing Ruler and iStat Menus, you can also consider the following products
MailHog - MailHog is an email testing tool inspired by MailCatcher, but easier to install.
SpeedFan - Hardware monitor for Windows that can access digital temperature sensors located on several 2-wire SMBus Serial Bus. Can access voltages and fan speeds and control fan speeds. Includes technical articles and docs.
Printix - Printix is a cloud-based print management platform.
Open Hardware Monitor - Monitors temperature sensors, fan speeds, voltages, load and clock speeds, with optional graph.
LAN Messenger - LAN Messenger is a decentralized UDP IM-style chat client which supports usernames...
Core Temp - Nov 4, 2017 - Core Temp is a compact, no fuss, small footprint, yet powerful program to monitor processor temperature and other vital information.