Recently I have been revisiting all the warframes I have so far, and try to getting the best of each one, so there is Limbo. One of the most hated warframes in the game apparently. But I found it is great for rescue missions in solo paying.
Not for the stealthy part of the mission, but for keeping the rescued alive. You simply vanish him/her to the void with your first hability and just go slow to the extraction point.