GNOME Web / Epiphany also saw another busy cycle of new work. I'm still personally opposed to the web browser due to it enabling ad-blocking by default and its impact on web publishers, but feature work here includes improving the bookmarks, async Storage Server support, various UI improvements, and continued work on privacy features.
GNOME Software continued maturing as GNOME's "app store." Notable to GNOME Software 3.24 is pretty solid support for Flatpak.
The GTK3 tool-kit continues receiving bug fixes and maintenance-focused work while GTK4 remains under development. One GTK3 addition is EGL X11 support. Some of the GTK4 development work over the past six months include more Wayland fixes, GTK4 Vulkan rendering support, OpenGL code refactoring, a frame recorder with frame-by-frame playback, better Windows support (including HiDPI), and a lot of other improvements. Arguably the biggest fundamental change was the introduction of the GTK Scene Kit.
For those working long days or just spending a lot of time on your computer at night, there is a "Night Light" mode in GNOME 3.24. This Night Light mode makes the GNOME desktop appear warmer automatically from sunset to sunrise or set manually between certain time periods. Science has proven warmer colors at night are recommended for helping avoid eye strain and sleeplessness.
The Nautilus file manager in GNOME 3.24 features Wayland improvements, improved handling for dealing with root files when trying to access them through sudo with an "admin back-end", and other minor alterations.