From Russia, probably without love, routed through Bulgaria via eBay:
They’re glass electrometer resistors from late in the Cold War:
That one presents 100 GΩ between its lead wires, which would count as open in any other circuit I’ve ever built.
The assortment arrived much richer than advertised, although I’d be even happier with a few more 10 GΩ and a few less 100 MΩ resistors. The 1000 GΩ = 1 TΩ resistor in the upper right seems absurd on the face of it, but there it sits.
I have no way to measure these, other than to build an electrometer amp and see what happens…