Tax foreclosures are different, and are done on a town-by-town basis. The Union Leader has tax lein/foreclosure auction lists published a couple times a week. There is a weekly newspaper which I can't recall the name of right now--will check it out and post here later today
You asked where you could find a list of government tax forclosures in NH.
The list you are seeking should be at your local Library. Ask the Librarian for the Registry Review. That's New Hampshire's legal newspaper that comes out weekly and has all the foreclosures--regardless of reasons why, (i.e. non-payment of taxes/non-payment of mortgage). It also contains the recent closings, (sales and prices paid by tax stamp and/or mortgage amount recorded) county by county. And a host of other information you will need--should you decide to jump into the swamp that is today's troubled real estate market. If you decide that picking up bargain real estate is for you, you can subscribe to the paper yourself, but you will find it a bit pricey unless you absolutely need it.