Stationary targets behind drop targets – EBD, Medusa, EBC.
Ball lock/path behind drop targets – FG, Fathom.
Remote controled drop targets – EBD, Xenon.

Shots only accessible w upper flipper – Embryon, FBII.
Shots behind upper flipper – SM.

Hidden ball return lanes (from upper pf to flippers) like Spectrum, Black Belt.

Physical ball lock that allows for stealing locked balls in multiplayer games – Fathom, FBII, Xenon.
Even better: connected physical ball locks like in Vector.

Collect bonus shots.

Outlanes that allow you to nudge draining balls back into play