Weird foam like glueless patches

[Chris S]

Almost anything sticky would do fine as it's going to be pressed against the inside of the tyre. I would even use vinyl tape in an emergency as long as I could stick it on the tube semi inflated so it wasn't too stretched once pumped up.

I tried that once - the tape moves when you pump up the tyre. If you use a bigger piece then it still doesn't stick properly and you get an air leak.