Force menu button in Android Lolipop I have a HTC One M8 with the 5.0 ROM (Play Edition) flashed on it. It's rooted.

I previously used VenomRoms which had an option to force the menu button, is there something similar on the default Lolipop rom?
By default, I assume you mean stock? Then no. Google did away with the menu button in Android 4.0. It's officially unsupported and appears (now called the "Action Overflow button") only when an app ignores design guidelines and requires it anyway. Google provides no direct way to force it, as it's officially no longer a part of Android.

Only custom ROMs or toolkit like Xposed modules can bring it back. An example module that includes such information is App Settings, although I can't speak to its Lollipop compatibility, especially since I think Xposed is still in early beta for Lollipop.