Alternatives to Cinnamon
Use a Linux desktop with a traditional application menu, panel and system tray. The listings below can replace it for an important use case. Each note says what changes if you switch.
The original
Cinnamon
Use a Linux desktop with a traditional application menu, panel and system tray.
Replacements
Listings that take over the same core job as Cinnamon.
KDE Plasma
Use a full Linux desktop with configurable panels, widgets and window behavior.
KDE Plasma is a full Linux desktop with more extensive appearance settings and KDE application integration, with defaults depending on the distribution.
GNOME
Use a Linux desktop organized around an activities overview and workspaces.
GNOME organizes the desktop around an activities overview and workspaces instead of a traditional menu and panel, and its shell extensions must match the installed version.
Xfce
Use a modular desktop environment built around traditional panels and windows.
Xfce keeps a traditional panel-and-windows layout in a modular desktop whose components distributions can combine, with versions depending on the distribution.
COSMIC
Use System76's desktop environment with configurable workspaces and window tiling.
COSMIC is System76's desktop with configurable workspaces and both tiling and floating workflows, needing a distribution and graphics stack that support the current release.
MATE
A traditional desktop environment for Linux and other Unix-like systems that continues the GNOME 2 design.
MATE keeps a traditional GNOME 2 style layout packaged in many distributions, though full releases arrive only every few years.
Budgie
A free and open source Linux desktop environment with its own panel, application menu and window management.
Budgie is a tidy Linux desktop environment with its own panel and application menu, actively developed and usually installed through a distribution.
Also worth comparing
These listings name Cinnamon as their own alternative, so the relationship runs both ways.
Enlightenment
A window manager, compositor and minimal desktop for Linux, BSD and other UNIX systems.
Cinnamon provides a traditional application menu, panel and system tray with applets, desklets and extensions, under GPL-2.0.
IceWM
A lightweight X11 window manager with a taskbar, workspaces and a familiar Windows-like layout.
Cinnamon provides a full Linux desktop with a traditional application menu, panel and system tray, plus applets, desklets and extensions.
LXQt
A lightweight, modular Qt-based desktop environment for Linux and BSD with X11 and Wayland sessions.
Cinnamon offers a traditional menu, panel and system tray with applets, desklets and extensions, under GPL-2.0.
Similar software
Related functionality, not a direct replacement.
Dash to Panel
Combine GNOME application shortcuts and the system tray in one panel.
Dash to Dock
Keep GNOME's application dash visible as a configurable dock.
xfce4-panel
Configurable panel for the Xfce desktop with plugins and applets.
Tint2
Lightweight panel and taskbar for Linux and BSD window managers.
BunsenLabs Linux
A Debian-based distribution with a preconfigured, lightweight Openbox desktop, continuing CrunchBang Linux.