Hi @Ad Infinitum
Based on my knowledge, add-ins can be built using VBA, COM, VSTO or Office Add-ins platform.
But VSTO add-ins does not apply to OneNote, Office Add-ins platform focuses on web add-ins.
You need the COM add-ins or VBA macros.
- For VBA macros, as you mentioned, some 3rd-party softwares can provide them that have been written.
- For COM add-ins, here is a similar thread "OneNote 2010 Ribbon addin", please refer to McLean Schofield's answer.
If you need further assistance, to help you better, I suggest you post a new thread on other forums of OneNote add-ins developer community, beacuse tags of "OneNote" or "OneNote Managemen" focus on general issues of OneNote.
Thanks for your understanding.
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