Gomockingbird was the best at this (for my purposes), but they decommissioned and didn't open source it like they said they would.

Balsamiq was next best and I use it still, but has a cumbersome user interface with enough friction that it gets in the way.

I tried using Excalidraw for a while, for my dislike of using Balsamiq, but for wireframing even with libraries it was too fiddly.

Just tried out Konty and it feels like an upgrade to Balsamiq for sure, and is clearly inspired by Excalidraw. Great work