Collect the pile, then unload it
1. Press ⌥⌘S to open the Stack panel.
2. Copy your items with ⌘C, one after another. Each copy lands under the previous one.
3. Take a screenshot with ⇧⌘4 if you need one. While the Stack is open, the shot joins the pile on its own, with no trip through your desktop folder.
4. Switch to the app you are filling in and press ⌃⌘V. The first item pastes and its row gets crossed out.
5. Press ⌃⌘V again for the second item, again for the third.
A counter in the panel shows how many are left, so you stop keeping the list in your head. The order is the order you copied in. Click any row and the queue restarts from that item, which is how I recover when I paste one field too far.
Text, links, images and files sit in the same queue, so a screenshot and a URL can be items 3 and 4 of the same job. You can also drag a file straight into the panel at the position you want, instead of copying it.
Dragging an item out of the Stack does not consume it. That difference matters: drag an image into Figma and it stays in the queue, while ⌃⌘V takes it out. Consumption only happens on paste.
The mode that surprises people
By default the Stack captures every ⌘C while it is open, and a plain ⌘V pastes the next queued item instead of the system clipboard. During a form-filling session that is what you want, because you keep the muscle memory you already have. It goes wrong when you leave the Stack open all afternoon and copy something for an unrelated reason.
The switch in the panel footer fixes it. Set it to ⌃⌘C and nothing enters the pile unless you press ⌃⌘C, and ⌘V belongs to macOS again. I keep the default on and close the panel when the job is done.
What I use
The Stack, because collecting references and refilling forms is the reason I forked a clipboard manager in the first place. It is part of Klipto Pro, which is $19.99 once with updates included and a 14-day trial.
If you only want to look back at things you copied, you do not need any of this. Maccy is free, open source and 1.6 MB, and it keeps a searchable history. It has no ordered queue. On macOS 26 Tahoe there is also a Spotlight clipboard history at ⌘Space then ⌘4, which holds plain text for 8 hours by default and lets you pick one item at a time by hand.