You're viewing a single thread.
Not the fact that you can't push and trip people without taking an entire ass subclass?
You can always take the shove action. PHB 195.
Using the Attack action, you can make a special melee attack to shove a creature, either to knock it prone or push it away from you. If you're able to make multiple attacks with the Attack action, this attack replaces one of them.
You only need the subclass (or the feat that gives you maneuvers) if you want to do it as part of your weapon attack.
Honestly, coming from Pathfinder 1e (where you needed a feat to use combat maneouvers without provoking an AoO) I was a real fan of 5e allowing for more use of those mechanics without paying a feat tax. It's unfortunate that they're rarely worth using in place of dealing damage, but that's a seperate issue. Shoving, Disarming and Grappling are available to everyone in 5e without any feat or class investment, at least.