If you want to be exhaustive about when the pin was possible, you need to look for masq/Kc/discard (militia, margrave, goons, cut purse, followers, arguably minion and b-crat); masq/Kc/Outpost; masq/outpost/Tr/discard; golem/masq/outpost/discarder (e.g. secret chamber, vault, etc.); golem/masq/discard/TR; golem/NV/outpost/discarder.
That said most of those are not going to work before the game ends.
On isotropic, I'd almost always go for the pin against folks who aren't extremely well informed players. Most people have no clue how it plays and even less about how to fight it. I would avoid it if there is an extremely quick megaturn option that can fire before I can win (e.g. KC/Bridge/support, HoP/big support).
Against well informed opponents (those who I think can do a decent job building a counter deck), I'd avoid the pin if there is good setup for a fast engine. I'd be more likely to go for the pin if there are cantrips out, particularly cheap cantrips.