Quote from Ertai Planeswalker »Champion of Lambholt can help your creatures get through. There's also Ohran Viper. Furthermore, Bow of Nylea can also discourage blocks and Dolmen Gate makes attacks less risky.
Quote from Anachronity »One With Nature is a fun Saboteur effect you can stick on one of your ETB ramp elves; you only need to connect once for it to be worthwhile.
There are also a lot of more sketchy artifact loot effects like Mask of Memory.