Numpad is a text editor/calculator hybrid.
From the HN comments, there is also calcpad ("A different take on the caculator"), an electron app where an online version is available too. Both nifty.
SSH Tips and Tricks, about Yubikey SSH forwarding, auto start tmux on connect and more (HN thread)
ansi-art — allows you to render a regular image as a 24-bit, Unicode-capable version of ANSI Art
ergodox; a next-generation ergonomic keyboard
standardebooks.org — Free and liberated ebooks, carefully produced for the true book lover.
Flipper Zero is an open-source, portable multi-tool for pentesters and geeks in a toy-like body (HN thread)
free-for.dev — A list of SaaS, PaaS and IaaS offerings that have free tiers of interest to devops and infradev
How a Doctor Killed the Baroque Era — Dr. John Taylor treated Bach and Handel with disastrous results, perhaps causing the death of both composers.