The collection includes some of the "best" and most popular toys in the 20th century - including a Bing locomotive, Shackleton trucks and Corgi boxed vehicles.
Dave Smith, manager of Bervie Auctions in Inverbervie, Aberdeenshire, said acquiring the "incredible" collection was a one-of-a-kind experience.
He said: "I've been doing this for 34 years and I haven't seen anything quite like it.
"It's just incredible - you rarely get a house with so many good-quality items, which have also been kept in a very good condition.
"It's one of the best collections we've ever had with an amazing selection of vintage toys, which haven't been seen in the area for a long time.
"It's quite overwhelming - there are just so many of them. The place at the moment looks like a little museum for old toys.
"There are Shackleton lorries, which are incredibly rare, enamel signs from an Edinburgh railway station and Edinburgh tram company, First World War tank, and thousands and thousands more."
Bervie Auctions came across "one of the best" selections of toys dating back to as far as the 1910s, when clearing an estate in the Capital.
The two-bedroom house is said to have been packed "from floor to ceiling" with thousands of rare and unique toys, which may have been collected in the span of 100 years.
Due to the large number of items, the auction house at Inverbervie has decided to hold two events for anybody who would like to join them for a blast from the past.
The first part of the action offering a mix of toys and enamel signs was taking place on Thursday at 6.30pm.
The second one, which will be dedicated to toys, will be held in a fortnight.
For the special sale of the rare collection, Bervie Auctions will also open doors to customers for the first time since the easing of lockdown restriction.
Mr Smith added: "We are definitely looking forward to the buzz of a live auction again."