Humble Bundle - region restrictions?

You'll have to look them up at the steam database, which games are they?

hard as hell to answer tbh. or at least i think?

most all of them will be regionfree, but not all.. for instance the COD BO3 MP Starter Pack was region locked to whatever region it was purchased.. but most typical bundle keys will be ROW.

google them or ask on each one i suppose is best bet really. there is no "key checker" of any type though no matter who may tell you differently.

Just look for the respective thread on SteamGifts in the "deal" section.
You'll probably will find some user that provided that info on the thread...

To answer this question, we would need to know where you are in the first place…

They shouldn't have any kind of region lock, as far as I'm aware... if you bought them from a store, that is.
But we need to know from which country you made the purchase to be sure.

Gifts from the Steam store, on the other hand, are always region locked to the region where they were bought.
Be aware that you cannot make a giveaway for Hitman 2: Silent Assassin, as it was given for free on Square Enix's online store last year.

In most cases there's no region lock on HB keys. That said, sometimes they have some seriously confusing region restrictions. It has more to do with the publisher than from where you got the key.
Check steamdb, and search the bundle's thread in the forum.