if you want useful starters, take my advice and don't touch the grass starters (Any of them.)
For the most useful, I'd say Skitty. It learns Attract (which is overpowered in RRT) and has Double-slap for Normal STAB and if you want coverage, it's very versatile. As for its partner, just pick up a Fire type (Charmander and Cyndaquil are best choices due to smokescreen) due to Skitty being able to cover The Fire Starter's water weakness with Shock Wave (and later thunderbolt) and Charmander/Cyndaquil being able to cover steel types that resist Skitty's STAB due to their Fire STAB