Tubolito?

Have you not ridden over a nail or some random sharp thing?

On tubeless? Yes, but never bad enough to have to fix at the roadside - by which I mean take the tyre off - plugging in a worm is a trivial fix. Off topic, though - if you've decided on tubes I'm not trying to evangelise.

I did research tubolitos as my spares for TCR last year as smaller, but didn't go for them in the end.