Some of the default items come with transparency but if you want to add some to the PS gradients, how ????
Select the gradient tool in Adobe ® Photoshop ® and then click the preset panel on the top option bar (left). The preset editor is now visible. Go to the top of the preset bar (transparency stops) and click (stop is then added), select. Go to the stops field at the bottom of the editor and set the stop to something less than 100% (for full transparency, set to 0). Personally, I like to add transparency to both of the far ends - setting the opacity to 0 and leave the inner stops to 100% or less. Of course, you can set the stops to any value depending on the transparency you want to achieve. You can also use the opacity midpoints to add more opacity or less opacity depending on the closeness to the individual stops. Just select the midpoint and move back and forth to change the color you see. The number of midpoints is two if you have three opacity stops, so always one less than the number of stops.
Go to the editor and set the opacity at the 0 position to 100% and then set the 25% position stop to 0% opacity and then 50% position to 100% opacity and 75% position at 0% opacity and the 100% position to 100% opacity. You can set the color stops to anything. You can make every complex combinations of 0% and 100% opacity to create more or less columns.
You can create the above columns and then add that to an image from left to right across an image in linear mode and then repeat with the same from top to bottom and you will have a basic grid from the presets
Set the opacity for the far left to 100% and click at 50% and then add a new opacity stop and set the opacity to 0% and then set the far right position stop to 100%. Apply using any colors from left to right with the linear mode and then from top to bottom to create a very quick frame.
Set the opacity stop from 100% at the far left and set the opacity to 100% for the far right. Set the 50% position opacity stop to 0% and then set the small midpoints to very close to the 50% position to create a super sharp line
Or use the midpoints close to the 0% position and the 100% position to create a thin line frame by applying that from left to right and top to bottom.
Just select the opacity stop and then delete key - though there has to be two opacity gradient stops in earlier versions of PS and with the most recent versions, it now can be one opacity stop.
Photoshop gradients may be of interest and use, there are over 32,000 presets in the set created for all kinds of uses in PS and PS Elements