Not exactly esoteric but I use PowerShell for everything. So it isn’t a mainstream language for many of my use cases since they’re not system admin related.

Lately I come back to posh [1] a modular and very simple (maybe even barebones) shell language. There is not much to it really, but the simplicity is a starting point for me. It gives me a bit execline [2] vibes.

[1] https://github.com/mikebolt/posh

[2] https://skarnet.org/software/execline/

Zig. I really enjoyed it and works well with WebAssembly. Definitively something I consider for low level while safe development.

Verilog. https://en.wikipedia.org/wiki/Verilog

Wren looked interesting: https://wren.io/

ABC Charity Esterel FL Fractran GPM Hope Lean MCPL NESL Oz ProTem Рапира rpython Squiggol UNITY USELESS

Vala - I really wish it had more support on Windows

Pike looked interesting at some point

Crystal

Haxe

Stoic - an Ur forth

BitGrid - a novel computational fabric

Gleam, Grain, Uiua

J, APL.