Stylem is described as 'A user style manager for Pale Moon, Basilisk, Interlink, SeaMonkey, and other Mozilla-based software. Install styles from userstyles.org to change how web pages and the application look' and is an app in the Development category. There are eight alternatives to Stylem for a variety of platforms, including Google Chrome, Firefox, Mac, Online / Web-based and Windows. The best alternative is Stylus, which is both free and Open Source. Other great apps like Stylem are Wikiwand (Free), Stylebot (Free, Open Source), FreeStylerWs (Free) and xStyle (Free, Open Source).
Styles and skins for all popular sites in the web FreeStyler is a browser add-on that has everything you might need to style up websites you visit according to your taste. It provides a great number of ready-to-use styles with convenient system of managing them.
A Chinese Developed Theme Manager. based on the source code of Stylish-for-Chrome 1.7.0. Restyle the web with xStyle, a user styles manager. With xStyle you can install themes & skins for many sites and create your own.
Introducing Cascadea, the first custom style manager designed as a Safari App Extension and native macOS app. Cascadea makes it easy to install custom styles that change the look and feel of any website you want.