This is a tangential thought from this answer, specifically the line "There are 10 and 12 pin DIPs".
After some searching around, I finally located only one 10-pin DIP part: NTE1450, 5 Watt audio power amplifier. The part is evidently obsolete, and the one datasheet I found, I cannot locate again.
I found many other components in 10-pin DIP though: LED displays, DIP switches, resistor packs and of course DIP sockets.
There are many 8 pin PDIPs 14 pin PDIPs flood the logic gate listings, but 10 and 12 are apparently pariahs. I haven't actually searched for a 12-pin DIP IC yet, but I suspect that too will be a rarity.
Why are 10-pin DIPs so uncommon?