I tend to use Nav Pro for most Foundry projects now, so bit rusty on the other options, but from memory Mega Menu will allow the inclusion of a button, which with a bit of lateral thinking could I guess launch a modal, perhaps not the default Foundry one though, not sure, would need to check.
But… And sorry, but this is the potentially annoying preachy bit… It’s not advisable to put anything in the menu bar that the user isn’t expecting. This of course is assuming your users won’t be expecting a modal!
What I mean is…
- Your logo will no doubt link to the home page.
- Your links without a down-pointing indicator will no doubt link to other pages.
- Links with a down-pointing indicator will open a drop down.
All that is standard, it’s how most menus work.
Now, if you fire into that lot a link that opens a modal, it’s not expected, so potentially bad practice and worse, confusing to users. And confused users tend to leave sites fast.
I know, that was a bit preachy, and it might be you know exactly what you are doing: There will always be good reasons to go against the norm. But I kinda figured it was worth mentioning, just in case.