Lost garage remote control
If you can tolerate appearing as if you are breaking and entering, you can use Daniel Gricom's solution with a bit of mechanical ingenuity. Many garage doors will have a small gap at the top, where the door meets the framing. If not, a wedge can be forced into the area near the center of the top.
This will allow you to drop a sturdy line from the top of the door, past the cylinder lock hole. The next tool required is an expandable noose or other gripper tool, but it has to fit either under the door or through the cylinder lock hole. The former is more likely but will also require a wedge in that location.
A quick search of the 'net leads me to believe that there is no off-the-shelf tool of this nature. This leaves a section of garden hose or similar tubing of sufficient length to reach from under the door to the internal manual door release. A section of braided cable, perhaps 1/16- 1/8&quot; diameter would be threaded into the hose with both ends free at the outside end of the hose. Stiffer is better as will be seen later.
The first line from the top is used to lift the hose to snare the handle. You'll have to have enough of a loop to extend from the inside surface of the door to the release handle, perhaps 24-30&quot;.
Twisting the hose from below the door will swing the loop until the snare can be effected.
The difficult portion of this requires one to see the snare and the handle. Two telephones with facetime or similar video capability is one method, again using the gap created by the wedge. The typical home colonoscopy kit, also known as a digital inspection camera will not have the focal length necessary, although the flexibility aspect is a boon.
Once the snare is around the handle, one should be able to pull the two loose ends and release the door.
One of the related answers in the margin suggests also a YouTube video using only a coat hanger. That particular garage has windows at precisely the level required for an easy open.