Right Mouse Navigation is a Blender add-on from SpectralVectors that maps Game Engine-style movement onto the right mouse button. Hold Right Mouse to switch into Walk Navigation and move through the scene using the W, A, S, D, Q and E keys, then click Right Mouse to reach Blender's standard context menus. A Time Threshold in the add-on preferences sets where a hold ends and a click begins.
The add-on can also extend to Node Editors as an optional mode. There, holding Right Mouse pans the view, while a click opens either the Node Context menu when a node is selected or the Node Search menu when nothing is selected. Both Left and Right Click Select are supported, though switching between them requires a Blender restart for the keymap to update correctly.
Version 2.8.0 adds Unity-style Middle Mouse and Alt key options, contributed by roguesleipnir. The add-on runs on Blender 4.2 LTS and newer, is released under the GNU General Public License v3.0 or later, and has been downloaded close to 30,000 times with a 5.0 rating across 56 reviews.