Tech Readout 3026 has a lot of the well known classics, like the Savannah Master, Demolisher, Schrek, Warrior VTOL, etc. https://www.sarna.net/wiki/Technical_Readout:_3026
You can also pick up a lot by browsing masterunitlist.info - See what different factions have available, check them out on Sarna, and see how they fit into different strategies.