My niche is pure JS widgets. That’s 100% Vanilla JS (old or new). No libraries or frameworks. I can create self-contained, state-aware, datastore driven (using session/application storage) interactive mini-applications, tools, widgets, and even games — often with just ONE JS file (CSS and HTML embedded), and fancier apps using maybe just a few supporting resource files. In fact, I am the only dev in my entire project of 100+ devs that has this skill and maintain quite a few of these widgets that I primarily authored. Thus is good and bad. Bad because it means I am stuck with these (and similar maintenance) forever and often get passed up for the newer stuff, but good because I’m almost irreplaceable.