The clipboard is the last resort when I build my actions because they leave a footprint. Unless you do a couple of extra steps to maintain a clipboard history, the value that runs through your apps will remain there and push the previous one into nothingness.

Some apps don’t give you a choice though and all you want is to access the iOS sharesheet. A Youtube video? A Vine short? An Instagram photo? None will let you access the built-in sharesheet and trigger extensions and your only alternative is to copy a link to the clipboard.

You possibly stumbled upon Workflow actions to download content from those sites. Here's one to download Youtube videos:

Download from Youtube Downloads video from Youtube. Takes the share URL as input. Get Workflow

Here’s another one by tomf64 to download Vine videos. This version was modified slightly to fix some quirks.

Download Vine Downloads video from Vine. Takes the share URL as input. Get Workflow

And the last one we’ll work with downloads images and videos from Instagram. I couldn’t find one I could give proper credit to the creator, so I built one myself.

Save From Instagram Downloads images and videos from Instagram and saves them into your Camera Roll. Get Workflow

If these actions take the URL as an input but the apps they’re related to only copy this URL to the clipboard, then we have to find a way to run Workflow actions with the clipboard set as input.

Trigger With Clipboard Runs any of your Workflow actions with the clipboard set as an input. Get Workflow

This action will list your workflows and run the one you choose with the clipboard as input. It only works for text in the clipboard and has the downside of opening Workflow when you run it from the Today Widget. That happens because it triggers the selected action using Workflow’s URL scheme.

I admit, this is only a workaround until the DeskConnect team figures out a way to call workflows within workflows so we can build modular actions. Would be like having x-callback-url built within Workflow and across its workflows. Until then, whenever I need to download a video or photo from one of the services I listed, I copy the link and pull down the Today Widget to run the action I need. It’s not great but gets the job done.